JP7797657B2 - Articulated robot - Google Patents

Description

The present invention relates to an articulated robot.

A horizontal articulated robot (SCARA robot) such as that disclosed in Patent Document 1 is well known. This horizontal articulated robot comprises a base fixed to a base and an articulated arm supported on the base. The arm comprises 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.

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

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

Japanese Patent Application Laid-Open No. 2009-226567

The present invention was made in consideration of the above-mentioned problems and aims to further reduce the inertia (moment of inertia) around the arm's rotation axis.

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 to rotate the first arm portion about the first axis, a second motor that is positioned 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 unit that connects the first arm portion and the second arm portion, transmits the rotational force generated by the second motor to the second arm, and deforms in response to the rotation of the second arm portion relative to the first arm portion.

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

A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[Configuration of articulated robot]
Fig. 1 is a perspective view showing a first embodiment of a horizontal articulated robot, which is an example of an 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.

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 work axis 7 provided at the tip of this robot arm 3.

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

The base portion 2 is a hollow, rectangular, rigid structure. 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 the motor body M1a. The reducer M1b is an RV reducer, a Cyclo reducer (registered trademark), a Harmonic Drive (registered trademark), or the like. The 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 the motor body. Note that the third motor M3, which will be described later, and the fourth motor M4 of the ninth embodiment, which will be described later, do not have a reducer.

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 to rotate (pivot) around the axis A1 by the first motor M1, with the base end serving as a fulcrum.

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

The working shaft 7 is located at the other longitudinal end (tip) of the second arm section 5, i.e., 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 section 5 and is supported so as to be able to move in the vertical direction (axial direction) and rotate around its axis relative to the second arm section 5, and is driven by the drive mechanism section 8.

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 rotates due to 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 vertically. The work shaft 7 also rotates due to the drive of the fourth motor M4. The fourth motor M4 is a hollow motor with a through-hole that penetrates vertically, and the work shaft 7 is arranged to pass through the center of the fourth motor M4 and the spline nut 31.

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

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 specific task on a workpiece, such as a chuck device for gripping and transporting the workpiece, a processing device for performing various processes on the workpiece such as welding, or a measuring device for measuring the workpiece, is attached to the tip of the work shaft 7.

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

As previously mentioned, 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 via the rotational force transmission unit 6 to the second arm unit 5, causing it to rotate (pivot) around the axis A2 with the base end of the second arm unit 5 as the fulcrum.

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 explained in detail below.

[Configuration of rotational force transmission section]
The second motor M2 that drives the second arm portion 5 is positioned 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.

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 response to changes in the distance between the first base 10 and the second base 12. The axes A3 and A4 are perpendicular axes that are parallel to each other, and the axis A3 is an example of the "third axis" of the present invention, and the axis A4 is an example of the "fourth axis" of the present invention.

The first base 10 is a hollow box-shaped member comprising 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, with a plate-like horizontal portion 20a that fits along the upper wall portion 4a of the first arm portion 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 portion 4. Therefore, when the second motor M2 is operated, the motor main body M2a and the first base 10 (frame 20) rotate together around axis A3 relative to the first arm portion 4.

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. Like 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, comprising a plate-shaped horizontal portion 22a that fits along the upper wall 5a of the second arm 5, and a plate-shaped upright portion 22b that rises vertically upward from one end of the horizontal portion 22a.

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. This sleeve portion 22d is held in the inner ring of a bearing B5 provided on the upper wall portion 5a of the second arm portion 5. With this configuration, the second base portion 12 is supported rotatably around the axis A4 relative to the second arm portion 5.

The telescopic 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.

Both links 14, 15 are elongated hollow plates with a thickness in the width direction (vertical direction in Figure 2) of the first link 14 and second link 15 (hereinafter sometimes referred to as the arm body). The first link 14 and second link 15 are overlapped at one longitudinal end in the thickness direction and connected to each other at this end so as to be rotatable around axis A5 extending horizontally. Specifically, the hollow shaft 14a provided on the side wall of the first link 14 is held in the inner ring of bearing B13 provided on the second link 15, thereby rotatably connecting the first link 14 and second link 15.

As shown in Figure 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.

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 around axis A6, which is parallel to 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 around axis A7, which is parallel to axis A5. Specifically, a hollow shaft 14b provided on the side of the first link 14 is held in the 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 in the 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 the "fifth axis" in the present invention.

As shown in Figures 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.

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. 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 sleeve 22d into the second arm 5. Of the cable 100, the cable for the first motor is connected to the first motor M1 within the base 2, and the cable for the second motor is connected to the second motor M2 within the first base 10. The cables for the third and fourth motors are connected to the third and fourth motors M3 and M4, respectively, within the second arm 5.

In addition, if a work tool (end effector) is attached to the work shaft 7, a cable for driving the work tool can also be routed together with the cable 100.

[Movement of Robot 1]
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.

Figures 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 axis A2 relative to the first arm portion 4. As previously described, 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 axis A3.

When the second arm portion 5 is driven in the forward direction by the second motor M2 while the robot arm 3 is in the neutral state, the second arm portion 5 rotates clockwise in a plan view (in the direction of the arrow R1 in the figure). As the rotation angle of the second arm portion 5 increases from the neutral state and the axis A4 and axis A3 approach each other, the telescopic portion 13 is folded so that the bending angle of the first link 14 and the second link 15 decreases, as shown in Figures 4(b), (c) and 5(b), (c).

On the other hand, when the second arm unit 5 is driven in the reverse direction by the second motor M2, the second arm unit 5 rotates counterclockwise in a plan view (in the direction of arrow R2 in the figure). Similarly, in this case, as the rotation angle of the second arm unit 5 increases from the neutral state, the telescopic unit 13 folds 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 telescopic unit 13 extends and retracts in response to the rotation of the second arm unit 5 relative to the first arm unit 4.

Although not shown in the figure, in addition to the rotational driving of the second arm portion 5 by the second motor M2, the first arm portion 4 is also 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 range indicated by the symbol Ar in Figure 5(a).

Figures 4 and 5 describe the movement 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 Figure 4. In other words, in a plan view of the robot 1, the second arm unit 5 can rotate clockwise (direction R1) or counterclockwise (direction R2) relative to the first arm unit 4, i.e., 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.

[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 (see Patent Document 1), is disposed closer to the axis A1 than the axis A2. This reduces the center of gravity of the robot arm 3, thereby reducing the inertia (moment of inertia) of the robot arm 3 around the axis A1. In this case, the rotational force of the second motor M2 is transmitted to the second arm unit 5 via the rotational force transmission unit 6. Therefore, the influence 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, including the motor body M2a and the reducer M2b, and the influence of the rotational force transmission unit 6 on the inertia is extremely small. Therefore, the configuration of the robot 1 described above can reduce the inertia of the robot arm 3 around the axis A1 compared to conventional horizontal articulated robots.

Furthermore, with this robot 1, it is possible to drive the second arm portion 5 around the axis A2 with torque and speed (angular velocity) comparable to when the second motor M2 is placed on the axis A2. This point will be explained below with reference to the drawings.

Figure 6 is a plan view model of the robot 1 in a neutral state. Figure 7 is a plan view model of the second arm unit 5 when in operation. In detail, this shows the state in which the second arm unit 5 is driven in reverse and the working shaft 7 is brought into contact with an obstacle, restricting the rotation of the second arm unit 5. Here, the link lengths B of the links 14, 15 of the extension/contraction section 13 of the rotational force transmission unit 6 are equal to each other, and 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.

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 × cos θ) (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.

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 portion 5 about the axis A2 is halved, making it possible to drive the second arm portion 5 about the axis A2 with torque and speed (angular velocity) comparable to 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.

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 axis A2 will be reduced to one-quarter. Therefore, with the robot 1 described above, compared to when the second motor M2 is positioned on axis A2, it is possible to reduce not only the inertia around axis A1 but also the inertia when the position of second motor M2 is used as the reference to the same or less, making it possible to increase the torque of second motor M2 without having to worry about the inertia around axis A1.

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 respects.

In the first embodiment, each link 14, 15 of the extension/contraction section 13 was bent so as to be convex upward and connected to each base 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 connected to each base 10, 12.

In the robot 1 of the second embodiment, when the second arm section 5 rotates relative to the first arm section 4, the extension/contraction section 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 (c). Therefore, the rotational force transmission section 6, like the first embodiment, transmits the rotational force of the second motor M2 to the second arm section 5 and deforms in response to the rotation of the second arm section 5. In other words, it extends and contracts.

The configuration of the robot 1 of the second embodiment described above can also achieve the same effects as 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 sections 4, 5 and the extendable section 13 when the extendable section 13 is folded as the second arm section 5 rotates.

[Third embodiment]
Fig. 9 is a schematic perspective view of the robot 1 according to the 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 (viewed from 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.

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

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

With this configuration of the robot 1 of the third embodiment, the same effects as those of the first embodiment can be achieved. Note that, from the perspective of avoiding interference between the second arm unit 5 and the telescopic unit 13, it is desirable that the angle θa between the axis A6 and the axis A3, and the angle θb between the axis A7 and the axis A4, be 90°, as in the first embodiment. If the angles θa and θb are less than 90°, there is a concern that the second arm unit 5 may interfere with the telescopic 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 telescopic unit 13 do not interfere with each other, for example, within a range of 10° or greater and less than 90°.

[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.

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 of the arm body (first arm section 4 and second arm section 5) in the width direction in a plan view (see Figure 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 of the arm body in the width direction, i.e., on a straight line intersecting the axes A2 to A4.

Specifically, the frames 20, 22 of each base 10, 12 have horizontal sections 20a, 22a formed in a disk shape, with standing sections 20b, 22b provided in their centers. 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 facing the first base 10 is bifurcated, and the first link 14 is rotatably connected to the standing section 20b with the standing section 20b inserted into the bifurcated portion. Similarly, the end of the second link 15 facing the second base 12 is bifurcated, and the second link 15 is rotatably connected to the standing section 22b with the standing section 22b inserted into the bifurcated portion.

In the robot 1 of the fourth embodiment, the second motor M2 is arranged inside the first arm portion 4. The second motor M2 is fixed to the upper wall portion 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 portion 10. Although not shown in the figure, the wiring structure of the cable 100 can be the same as that of the fifth and sixth embodiments described below.

In the case of 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 telescopic portion 13 is folded so that the bending angle between the first link 14 and the second link 15 becomes smaller, as shown in Figures 11(b), (c), (d) and (e).

The configuration of the robot 1 of the fourth embodiment allows for the same effects as those of the first embodiment to be achieved. In addition, with the robot 1 of the fourth embodiment, the rotational force transmission unit 6 is configured so that the extension/contraction unit 13 is positioned on the inner side of the arm body in the width direction when the robot arm 3 is in the neutral state, which has the advantage of making the entire robot more compact than the robot 1 of the first embodiment.

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.

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

The cable 100 is guided from the base 2 into the second arm 5 through the cable piping L1. 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.

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

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 the first embodiment.

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.

In the first embodiment, a flexible cable pipe L1 (not shown in Figure 1) made of a flexible tube was provided, and the cable 100 was guided from the base portion 2 to the rotational force transmission portion 6 through this cable pipe L1. 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 above the base portion 2.

The cable guide section 40 has an inverted L-shape, with a vertical guide section 41 extending upward from the top surface of the base section 2 and a horizontal guide section 42 extending horizontally from the top end of the vertical guide section 41. The vertical guide section 41 is located on the top surface of the base section 2, outside the movable range of the first arm section 4. The horizontal guide section 42 is located above the top surface of the first arm section 4, with its tip positioned on the axis A1.

An opening 42a is formed on the underside of the tip of the lateral guide portion 42 at a position corresponding to the axis A1. In addition, an opening 4c facing the opening 42a is formed on the upper surface (upper wall portion 4a) of the first arm portion 4.

As shown in Figure 13, the cable 100 is introduced into the cable guide section 40 through the opening 2b formed in the upper wall section 2a of the base section 2, guided from the cable guide section 40 into the interior of the first arm section 4 through the openings 42a and 4c, and 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 within the first arm section 4, and the cables for the third and fourth motors are connected to the third motor M3 and fourth motor M4, respectively, within the second arm section 5. The cable for the first motor is connected to the first motor M1 within the base section 2, as in the first embodiment.

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.

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 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.

Seventh Embodiment
14 is a vertical cross-sectional view of the essential parts of the robot 1 according to the seventh embodiment. The robot 1 according to the seventh embodiment differs from the first embodiment in the following respects in the wiring structure of the rotational force transmission unit 6 and the cable 100.

In the robot 1 of the seventh embodiment, the second motor M2 is arranged on the axis A1. That is, the second motor M2 is arranged with respect to the first arm portion 4 so as to generate a rotational force about the axis A1, and the rotational force transmission unit 6 is provided to correspond 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 length of each link 14, 15 differs from that in the first embodiment.

In addition, 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 has an opening 21a at a position opposite the opening 42a of the cable guide section 40 (lateral guide section 42), i.e., on the axis A1.

As shown in Figure 14, the cable 100 is introduced into the cable guide section 40 through the opening 2b formed in the upper wall section 2a of the base section 2, and is guided from the cable guide section 40 through the openings 42a and 21a into the interior of the first base section 10 of the rotational force transmission section 6. Then, as in the first embodiment, the cable 100 is guided through the interior of the rotational force transmission section 6 to the tip of the second arm section 5.

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 the first embodiment. Moreover, in the seventh embodiment, the second motor M2 is arranged 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 arranged on the axis A3. Therefore, according to the robot 1 of the seventh embodiment, the inertia (moment of inertia) of the robot arm 3 around the axis A1 is reduced compared to the robot 1 of the first embodiment.

Eighth Embodiment
15 is a cross-sectional view of a main part of a robot 1 according to the 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 ). A rotational force transmission unit 6 is provided corresponding to the arrangement of the second motor M2. The basic configuration of the rotational force transmission unit 6 is the same as that of the first embodiment.

Specifically, in the eighth embodiment, the second motor M2 is arranged to vertically pass through the lateral guide portion 42 of the cable guide unit 40 via 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 arranged 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.

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 4c along the second motor M2 into the interior of the first arm 4. The cable 100 is then guided through the interiors of the first arm 4 and the second arm 5 to the tip of the second arm 5.

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 the first embodiment. Furthermore, in the eighth embodiment, the second motor M2 is arranged on the axis A1, which is the center of rotation of the first arm section 4. 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 around the axis A1 compared to the robot 1 of the first embodiment.

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 differs from the sixth embodiment in the following respects in the specific configurations of the working shaft 7 and the drive mechanism 8.

In the robot 1 of the ninth embodiment, the working shaft 7 is a ball screw spline shaft, and is arranged on the axis A4 so as to vertically penetrate the second base 12 of the rotational force transmission unit 6. More specifically, the working shaft 7 vertically penetrates the second base 12 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.

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

Specifically, the third motor M3 and the fourth motor M4 are arranged facing each other vertically between the axes A4 and A2 on the second arm 5, with their output shafts positioned within the second arm 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 5. When the ball screw nut 36a and the ball spline nut 38a are driven to rotate in synchronous fashion by the third motor M3 and the fourth motor M4, the working shaft 7 rotates about the axis A4.

In the ninth embodiment, the drive mechanism unit 8 is thus composed of 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.

The basic structure of the robot 1 of the 9th embodiment is the same as that of the first embodiment, and therefore the robot 1 of the 9th embodiment can also enjoy the same effects as the first embodiment.

In addition, in the robot 1 of the ninth embodiment, the working shaft 7 is arranged on the axis A4 and is configured to vertically pass through the second base 12 of the rotational force transmission unit 6. Therefore, when the second arm unit 5 is in operation, the rotational force transmission unit 6 does not interfere with the drive mechanism unit 8 of the working shaft 7. Therefore, the movable area Ar of the second arm unit 5 is not restricted in order to avoid such interference; in other words, this has the advantage of contributing to an increase in the movable area Ar.

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

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 in the tenth embodiment consists of a magic hand-type link mechanism (lage tongs) that combines multiple parallel link mechanisms, as shown in Figure 17.

In addition, some or all of the individual links that make up the telescopic section 13 have a hollow structure, and the cable 100 that is guided from the base section 2 to the rotational force transmission section 6 through the cable piping L1 is guided to the tip of the second arm section 5 through the inside of the link of the telescopic section 13. This is the same as in the first embodiment.

The basic structure of the robot 1 of the 10th embodiment is the same as that of the first embodiment, and therefore the robot 1 of the 10th embodiment can also enjoy the same effects as the first embodiment.

Furthermore, with the magic hand-type telescopic unit 13 (lage tongs) as described above, when the axis A4 and axis A3 are closest to each other as the second arm unit 5 rotates, i.e., when the telescopic unit 13 is folded to its smallest size, the height of the upper end of the telescopic unit 13 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.

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 specific configuration of the rotational force transmission unit 6 in the following respects.

18 and 19, in the robot 1 of the eleventh embodiment, the first link 14 constituting the extension/contraction section 13 of the rotational force transmission section 6 is composed of a first section 141 connected to the second link 15, a second section 142 connected to the first base section 10 (frame 20), and a connecting section 16 that connects these sections 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, perpendicular to axes A5 to A7. The connecting section 16 is composed of a bearing such as a cross roller bearing, with the inner ring of the bearing fixed to the first section 141 and the outer ring fixed to the second section 142.

The robot 1 of the 11th embodiment allows the rotational force generated by the second motor M2 to be transmitted more smoothly to the second arm portion 5 via the rotational force transmission unit 6. In other words, if the precision 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 when the rotational force transmission unit 6 operates. The configuration of the 11th embodiment allows relative rotation between the first portion 141 and the second portion 142, allowing the aforementioned unnecessary forces 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 may be transmitted more smoothly to the second arm portion 5.

In the example of Figure 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. Furthermore, while 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, if 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 Figure 19.

Although not shown, the tenth embodiment (see Figure 17) can also adopt a configuration similar to that of the eleventh embodiment. In this case, a connecting portion 16 can be provided on the link member connected to the first base portion 10 or the link member connected to the second base portion 12, among the link members that constitute the multiple parallel link mechanisms of the extension/contraction portion 13.

[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.

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

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. The shaft lengths L50 and L52 are set so that when the robot arm 3 is in the neutral state, the tip of the shaft member 50 is inserted into the tip of the guide member 52 at a position approximately midway between the axes A6 and A7, and so that when 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 the guide member 52).

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 this holder member 51 around 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 this holder member 53 around axis A6. Specifically, as shown in FIG. 21 , the 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. The 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.

As shown in Figure 22, the second motor M2 is oriented upward, as in the sixth embodiment (see Figure 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.

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 Figure 13). That is, the cable guide section 40 is provided on the upper part of the base section 2. The cable 100 is introduced from the base section 2 into the cable guide section 40. It is then guided through the cable guide section 40 into the interior of the first arm section 4, and further guided from the first arm section 4 to the tip of the second arm section 5 through the hollow shaft 5c.

Figures 23 and 24 are explanatory diagrams of the operation of the robot 1 of the twelfth embodiment, with Figure 23 being a perspective view and Figure 24 being a plan view, each showing the operation of the robot 1. Note that in Figures 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.

Figures 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 while the robot arm 3 is in the neutral state, the second arm unit 5 rotates clockwise (in the direction of arrow R1) in a plan view. 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 extension/retraction unit 13, as shown in Figures 23(b), (c) and 24(b), (c).

On the other hand, when the second arm unit 5 is driven in the reverse direction by the second motor M2, the second arm unit 5 rotates counterclockwise (in the direction of arrow R2) in a plan view. Similarly, in this case, 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 telescopic unit 13, as shown in Figures 23(d) and (e) and 24(d) and (e). In other words, the telescopic unit 13 extends and retracts in response to the rotation of the second arm unit 5 relative to the first arm unit 4.

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

The basic structure of the robot 1 of the 12th embodiment is the same as that of the first embodiment, and therefore the robot 1 of the 12th embodiment can also enjoy the same effects as the first embodiment. Moreover, in the robot 1 of the 12th embodiment, the extension/contraction section 13 of the rotational force transmission section 6 is composed of the shaft member 50 and 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.

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.

In addition, the telescopic section 13 may have a structure (double row) in which multiple rows of pairs of shaft members 50 (spline shafts or rail members) and guide members 52 (spline nuts or sliding members) are arranged.

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.

In the thirteenth embodiment, as in the third embodiment (see Figure 9) described above, the angle formed by axis A6 with respect to axis A3 and the angle formed by axis A7 with respect to 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 tilted relative to the vertical.

In the configuration of the 13th embodiment, as in the 12th embodiment, when the second arm portion 5 rotates relative to the first arm portion 4, the extension/contraction portion 13 contracts in response, as shown in Figures 25(b) and (c). Therefore, as in the robot 1 of the 12th embodiment, the rotational force transmission portion 6 transmits the rotational force of the second motor M2 to the second arm portion 5 and extends/contracts in response to the rotation of the second arm portion 5.

The basic structure of the robot 1 of the 13th embodiment is the same as that of the 12th embodiment. Therefore, the robot 1 of the 13th embodiment can also enjoy the same effects as the 12th embodiment.

In addition, 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 perspective of avoiding interference between the second arm portion 5 and the telescopic portion 13. If these angles are smaller than 90°, there is a concern that the second arm portion 5 will interfere with the telescopic portion 13. Therefore, in the thirteenth embodiment, the angles are set within a range in which the second arm portion 5 and the telescopic portion 13 will not interfere with each other, for example, a range of 10° or greater but less than 90°. This is the same as in the third embodiment described above.

[Fourteenth embodiment]
Fig. 26 is a cross-sectional view taken along a vertical plane of the robot 1 according to the fourteenth embodiment. Fig. 27 is a perspective view of the robot 1, with (a) in the figure showing 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 respects.

In this example, the rotational force transmission section 6 is configured so that the extension/contraction section 13 is parallel to a plane perpendicular to axes A2 to A4.

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. In other words, the robot 1 of the 14th embodiment is configured such that rotation of the shaft member 50 around axis A7 is restricted, and rotation of the guide member 52 around axis A6 is restricted.

In the case of 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).

In the 14th embodiment, both rotation of the shaft member 50 around axis A7 and rotation of the guide member 52 around axis A6 are restricted, for the following reasons.

In a configuration such as the twelfth embodiment shown in Figures 20 to 24, in which the heights of both ends of the extension/contraction section 13 (i.e., the heights of axis A6 and axis A7) are different, a difference in the vertical tilt of the shaft member 50 and the vertical tilt of the guide member 52 occurs as the second arm section 5 rotates. Therefore, it is necessary to allow rotation of the shaft member 50 about axis A7 and rotation of the guide member 52 about axis A6 to absorb 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 section 13 are equal, no difference in tilt occurs between the shaft member 50 and the guide member 52 even when the second arm section 5 rotates. Therefore, even if the rotation of the shaft member 50 about axis A7 and the rotation of the guide member 52 about axis A6 are both restricted, the operation of the rotational force transmission section 6 is not impaired.

The basic structure of the robot 1 of the 14th embodiment is the same as that of the 12th embodiment, and therefore the robot 1 of the 14th embodiment can also enjoy the same effects as the 12th embodiment.

Furthermore, according to the robot 1 of the fourteenth embodiment, when the entire rotational force transmission unit 6 including the extendable unit 13 is positioned on the widthwise inner side of the arm body (first arm portion 4 and second arm portion 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 the components for rotatably supporting the shaft member 50 and guide member 52 (the bearings B14, 15, the holder members 51, 53) are no longer necessary.

[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 respects.

In the 15th embodiment, as shown in Figure 28, the shaft member 50 is rotatably supported by the holder member 51 via a bearing B30 in the extension/contraction section 13. In the 15th embodiment, this configuration makes it possible to more smoothly transmit the rotational force generated by the second motor M2 to the second arm section 5 via the rotational force transmission section 6.

As explained in the 11th embodiment, if the precision of 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, guide member 52, or 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 15th embodiment, relative rotation (rotation around 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, which in turn enables the rotational force generated by the second motor M2 to be transmitted to the second arm unit 5 more smoothly.

In the example shown in Figure 28, the shaft member 50 is rotatably supported relative to the holder member 51, but the guide member 52 may also be rotatably supported relative to the holder member 53. In this case, the same effect can be achieved.

Also, while maintaining the structure in which the shaft member 50 is fixed to the holder member 51 and the guide member 52 is fixed to the holder member 53, the shaft member 50 and the guide member 52 may be configured to allow relative rotation. In this case, smooth operation can be achieved by, for example, configuring the shaft member 50 as a ball bushing shaft and the guide member 52 as a ball bushing nut. This configuration can also achieve the same effects as the configuration in Figure 28.

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 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, since the fourteenth embodiment is configured to restrict rotation of the shaft member 50 around axis A7 and restrict rotation of the guide member 52 around axis A6, the effect of smoothly transmitting the rotational force generated by the second motor M2 to the second arm portion 5 is low.

Sixteenth Embodiment
29 is a plan view (partial cross-sectional view) of the robot 1 according to the 16th embodiment. The robot 1 according to the 16th embodiment has the same basic configuration as the robot 1 according to the 12th embodiment (see FIGS. 20 to 24), but differs in the configuration of the rotational force transmission unit 6 in the following respects.

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, when the robot arm 3 is in a neutral state, 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.

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 rearward from the first arm section 4, i.e., toward the axis A1 (toward the base section 2).

In the twelfth embodiment (see Figures 20 to 24), the axial lengths L50, L52 of the shaft member 50 and 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 robot arm 3's neutral state. Therefore, it is conceivable that the axial lengths L50, L52 of the shaft member 50 and 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 guide member 52. Therefore, the robot 1 of the sixteenth embodiment contributes to an increase in the movable range of the robot arm 3.

[Seventeenth 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 respects.

In the 17th embodiment, the guide member 52 constituting the extension/retraction 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 their axis. In other words, the extension/retraction section 13 has a telescopic structure that can be extended and retracted in two stages, with the outer guide member 52a and the inner guide member 52b 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.

Of the guide members 52, the base end of the outer guide member 52a is fixed to the holder member 53. The telescopic section 13 further includes a biasing member that biases 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.

In the robot 1 of the 17th embodiment, the telescopic section 13 has a structure that allows it to be extended and retracted in two stages, so the degree of freedom in the extension length of the telescopic section 13 is higher than in the robot 1 of the 12th embodiment. In other words, when the second arm section 5 rotates, the telescopic section 13 can be retracted further. This contributes to expanding the movable range Ar of the robot arm 3.

In addition, the inner guide member 52b is biased in opposite directions by coil springs 55, 56 on both sides of its axis, so its position is stably maintained relative to the shaft member 50 and the outer guide member 52a. This suppresses or prevents the inner guide member 52b from moving unstably during operation of the robot arm 3.

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

In the example shown in Figure 30, the telescopic section 13 is configured to be telescopic in two stages, but as shown in Figure 31, the telescopic section 13 may also be configured to be telescopic in three stages. Specifically, the guide member 52 is composed of 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 their axes. In other words, the telescopic section 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 composed of a spline shaft, the first and second inner guide members 52b and 52c are composed of the composite cylindrical body, and the outer guide member 52a is composed of a cylindrical spline nut.

Furthermore, as biasing members, a coil spring 55a is disposed between the holder member 51 and the end of the first inner guide member 52b on the second base 12 side, and a coil spring 55b with a smaller diameter than the coil spring 55a is disposed between the holder member 51 and the end of the second inner guide member 52c. Furthermore, a coil spring 56a is disposed between the holder member 53 and the end of the first inner guide member 52b on the first base 10 side, and a coil spring 56b with a smaller diameter than the coil spring 56a is disposed between the holder member 53 and the 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 disposed inside the larger diameter coil spring 55a and on the outer periphery of the shaft member 50, while the larger diameter coil spring 55a is disposed 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 within the first spring accommodating recess 531, and the small diameter coil spring 56b is arranged inside the large diameter coil spring 55a and within the second spring accommodating recess 532 further formed on the inner bottom of the first spring accommodating recess 531.

The configuration shown in Figure 31 allows for greater flexibility in the extension length of the extension section 13. Furthermore, 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.

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

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

Figure 32 is an oblique view of a vertical articulated robot. The vertical articulated robot 1' shown in the figure comprises a base unit 200 installed on a base BP and a robot arm 300 supported by this base unit 200.

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 whose base end is rotatably connected to the first arm section 210 around an axis A12 perpendicular to the axis A11, a third arm section 230 whose base end is rotatably connected to the tip end of the second arm section 220 around an axis A13 parallel to the axis A12, a fourth arm section 240 whose base end is rotatably connected to the tip end 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 portion 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.

The first arm portion 210 is driven to rotate around axis A11 by a first arm motor (not shown) arranged on the base portion 200, the second arm portion 220 is driven to rotate around 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 around 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 around 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 around axis A15 by a fifth arm motor M5 (shown in Figure 33) arranged within the fourth arm portion 240.

Figure 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 the figure, the fourth arm portion 240 has an arm support portion 241 extending forward at one end in the width direction (vertical direction in Figure 33) of its tip portion. The fifth arm portion 250 is rotatably supported by this arm support portion 241. Specifically, a hollow shaft 251 provided on the side wall portion of the fifth arm portion 250 is held by the inner ring of a bearing B40 provided on the arm support portion 241. This allows the fifth arm portion 250 to be rotatably connected to the fourth arm portion 240 around axis A15.

The fifth arm motor M5 that drives the fifth arm section 250 is not located on the axis of 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 axis A15 on the opposite side along axis A14 (a position spaced apart from the base end of the fourth arm section 240).

The fifth arm section 250 is driven to rotate around axis A15 by the rotational force generated by the fifth arm motor M5 being transmitted via the rotational force transmission section 60.

The configuration of the rotational force transmission unit 60 is substantially the same as the configuration of the rotational force transmission unit 6 described in the fourteenth embodiment (Figure 26). That is, the rotational force transmission unit 60 includes a first base 110 that rotates about axis A17 due to the rotational force of the fifth arm motor M5, a second base 120 that is rotatably supported about axis A18 relative to the fifth arm unit 250 via bearing B42, and an expansion/contraction unit 130 that connects the first base 110 and the second base 120 and deforms (expands and contracts) in response to changes in the distance between the first base 110 and the second base 120. Axis A17 and axis A18 are both parallel to axis A15.

The telescopic section 130 is composed 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 fixed to the second base 120 and the base end of the guide member 152 fixed to the first base 110. The shaft member 150 and 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.

In other words, 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 section 13 extends and retracts accordingly.

With this configuration of robot 1', the fifth arm motor M5 that drives the fifth arm section 250 is not located in the fifth arm section 250, but is located inside the fourth arm section 240, at a position offset from axis A15 to the opposite side along axis A14. This reduces the weight of the fifth arm section 250 and reduces the inertia (moment of inertia) of the fifth arm section 250 around axis A15. Furthermore, the fifth arm section 250 can be made more compact.

In the 18th embodiment, the fourth arm portion 240 corresponds to the "first arm portion" of the present invention (claim 17), and the fifth arm portion 250 corresponds to the "second arm portion." Furthermore, 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." Furthermore, the fifth-arm motor M5 corresponds to the "motor" of the present invention.

The articulated robots according to the first to eighteenth embodiments of the present invention have been described above. However, the articulated robots according to these 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.

The present invention can be summarized as follows:

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 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.

With this articulated robot configuration, the second motor for driving the second arm section is positioned closer to the first axis than the second axis of the first arm section, 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 positioned on the second axis. Furthermore, with regard to the second arm section, the inertia based on the position of the second motor can be reduced compared to when the second motor is positioned on the second axis. Therefore, with this articulated robot configuration, it is possible to effectively reduce the inertia around the rotation axis of the arm of the articulated robot.

In the above-mentioned articulated robot, the second motor generates a rotational force around a third axis parallel to the first and second axes, and the rotational force transmission unit includes a first base that rotates around the third axis due to the rotational force of the second motor, a second base supported on 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 expands 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.

With this configuration, the rotational force of the second motor can be transmitted to the second arm portion via the rotational force transmission portion, allowing the second arm portion to rotate smoothly relative to the first arm portion.

In this case, it is preferable that the extension/contraction section be made up of a link mechanism. This configuration allows the rotational force of the second motor to be transmitted to the second arm section with a relatively simple structure, while allowing the rotational force transmission section to smoothly deform (extend and contract) in accordance with the rotation of the second arm section.

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, and 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 be 90°.

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

Furthermore, in the above-mentioned articulated robot, if 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 about an axis perpendicular to the third axis, and the other end is rotatably connected to the second base about an axis perpendicular to the fourth axis.

This configuration is advantageous in keeping the occupied height of the link mechanism low when the link mechanism is folded as the second arm portion rotates.

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.

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 when the rotational force transmission unit operates. The above configuration allows relative rotation between the first and second portions, allowing the aforementioned unnecessary forces to be released. 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.

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

This configuration achieves a rational configuration in which the interior of the rotational force transmission section is utilized as cable routing space.

In addition, in the above-mentioned articulated robot, the telescopic 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.

In this configuration, too, the rotational force of the second motor can be transmitted to the second arm portion with a relatively simple configuration, while the rotational force transmission portion can be smoothly deformed (extended and contracted) in accordance with the rotation of the second arm portion.

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 be 90°.

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

When the telescopic portion comprises the shaft member and the guide member, it is preferable that the telescopic portion be arranged parallel to a plane perpendicular to the second axis and the third axis.

With this configuration, the rotational force transmission part can be smoothly deformed (expanded and contracted) in conjunction with rotation of the second arm part without the shaft member and guide member being rotatably supported relative to the first base part and the second base part.

In the above-mentioned articulated robot, one side of the shaft member and the guide member may be rotatable about an axis relative to the first base or the second base that supports that side. Furthermore, the shaft member may be rotatable relative to the guide member.

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 when the rotational force transmission unit operates. The above configuration allows the aforementioned unnecessary forces to be released, enabling the rotational force transmission unit to operate smoothly, and as a result, the rotational force generated by the second motor to be transmitted more smoothly to the second arm portion.

In addition, in the above-mentioned articulated robot, the guide member may be composed of multiple unit guide members with a telescopic structure that are arranged concentrically on the shaft member and can slide relative to each other.

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

In this case, when the outermost unit guide member among the plurality of unit guide members is defined as the outer guide member and the unit guide member arranged inside the outer unit guide member is defined as the inner guide member, the outer guide member may be connected to the base on the other side, and the extendable portion may include biasing members arranged on both sides of the inner guide member in the axial direction, each of which includes 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 base on one side toward the base on the other side.

This configuration ensures that the position of the inner guide member is stably maintained relative to the shaft member and the outer guide member. This suppresses or prevents the inner guide member from moving unstably during operation of the robot arm 3.

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 on the second arm portion so as to be rotatable about a third axis parallel to the second axis; and an extension/contraction unit connecting the first base portion and the second base portion, the extension/contraction unit extending and 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.

This articulated robot configuration makes it possible to effectively reduce the inertia (moment of inertia) of the second arm section when the position of the second motor is used as the reference, compared to when the second motor is positioned on the second axis.

Claims (14)

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,
The other end of the second link member is rotatably connected to the second base portion around an axis parallel to the fifth axis . The articulated robot according to claim 1 ,
The articulated robot is characterized in that the predetermined angle is 90°. 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; 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 . 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. 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. 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. The articulated robot according to claim 7 ,
The articulated robot is characterized in that the predetermined angle is 90°. 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. 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. 10. The articulated robot according to claim 6 , wherein the shaft member is provided so as to be rotatable relative to the guide member. 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.
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. 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.