JPS637285A - Industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an industrial robot, and particularly to a link mechanism that constitutes an arm of an industrial robot.

(Conventional technology) Recent industrial robots (hereinafter referred to as robots) are designed to improve positioning accuracy and operating speed.

Direct drive motor that does not use a reducer (hereinafter referred to as DD)
motor) is used.

By the way, when a sufficient torque is required for a DD motor, the external size becomes large. Therefore, it is advantageous to dispose the DD motor at the center of the mechanism, rather than at the tip of the robot.

Therefore, the arrangement of the DD motor and its power transmission mechanism are important, and transmission by a belt drive or a link @ mechanism is common, and basically it is a mechanically serial arm configuration. Figures 10 and 11 show link configurations that have been widely used in the past. Links 1a and 1b are basic arms, and are articulated by link 2a and link 2b, which are drive arms. 3,4
make a rotational movement around the In FIG. 10, reference numeral 5 indicates the joint between link 1b and link 2b, and reference numeral i indicates the load inertia.

Reference numeral m indicates a motor; in FIG. 11, reference numeral 6 indicates a joint between link 1b and link 1a; reference numeral i indicates load inertia; and reference numeral m indicates a motor.

(Problems to be Solved by the Invention) FIG. 12 shows that the link 1a of the link mechanism constituting the arm shown in FIG. 10 is fixed (θ1 axis fixed), the links 1a, 2
This figure shows the nodal force applied to the link 1b when b is accelerated or decelerated. Since an inertia force Fi of load inertia i is applied during acceleration or deceleration, a bending moment of FiXul is applied to the link 1b. Here, Ql is the distance from the center of the load inertia j to the joint 3. In addition, FIG. 13 shows the link 1a of the arm mechanism shown in FIG.
This shows the nodal force applied to link 1b when links 2a and 2b are adjusted (fixed on the The bending moment of FiXQ3 is added. Here, ρ is the distance from the center of the load inertia j to the joint 4.

By the way, even if this bending moment is applied, link 1b
In order to prevent bending of the link 1b, the rigidity of the link 1b must be sufficiently large. However, the link 1b, which has increased rigidity and is prevented from vibrating, inevitably has a large mass, and therefore a large load is applied to the motor during acceleration and deceleration. Moreover, as can be seen from FIGS. 13 and 14, the reaction force F14. applied to the joint 3°4. Since F1m also increases, bearings for joint 3.4 must be made with high rigidity in order to extend their lifespan and ensure smooth operation.Here, F is Fll, +2 and F.
Resultant force of 13W2 (However, Fta!2=Fl”F1g!
+Fts! = (Q @/ Q L) XFi) and * FLs is Fl. and the resultant force of Fl and y (however.

F1□= Fi+F, ,□, F1□t = (I2s
/Ω,)XFi).

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a robot that improves operating speed and acceleration/deceleration, extends the life of the parts that make up the joints, and eliminates vibrations caused by link deflection to provide stable operation.

[Structure of the invention] (Means and effects for solving the problems) The present invention has the following features:
! [A frame body having a surface, and a first direct drive motor and a second direct drive motor concentrically attached to the frame body.

A group of four links, including a link driven by the first direct drive motor and a link driven by the second direct drive motor, are arranged horizontally and connected in a rectangular shape that can be expanded and contracted to form an arm. It consists of a link mechanism, and a main shaft that can be moved up and down and rotated by a drive device attached near the tip of the link mechanism.

When the link mechanism is swung, a bending moment is not generated in the front link, and the nodal force is reduced.

(Example) Hereinafter, an example of the industrial robot of the present invention will be described with reference to the drawings. 1 and 2, the industrial robot 10 includes a frame 11 whose bottom surface is the installation surface, and a first DD motor (hereinafter θ
(referred to as a □axis DD motor) 12, and a second DD mounted on the upper part of the frame 11 concentrically with this θ1 axis DD motor 12.
A motor (hereinafter referred to as the θ8-axis DD motor) 13, a link (hereinafter referred to as the rear θ1-axis link) 14 whose end is connected to the hollow rotating shaft 12a of the θ-axis DD motor 12, and the rear side 01 A link 15 (referred to as rear θ axis link) disposed above the shaft 14 and whose end is connected to the rotating shaft 13a of the θ2-axis DD motor 13, and a rear θ1-axis link 14.
a link (hereinafter referred to as front θ 1-axis link) 16 arranged at the upper part of the rear θ axis link 14 and rotatably connected to the other end of the rear θ 1-axis link 14; A link (hereinafter referred to as front θ2411 link) 17 rotatably connected to the other end of the rear θ2-axis link 15, and a θ□-axis DD motor 12 on the upper part of the rear θ2-axis link 15.
and a DD mounted concentrically with the θ2-axis DD motor 13
Motor (hereinafter referred to as θ axis DD motor) 18 and front side θ
□ Drive bag f! is attached to the other end of the shaft link 16 and raises and lowers the main shaft (hereinafter referred to as Z-axis) 19! (hereinafter referred to as 2M drive device) 20, an intermediate shaft 21 that is rotatably supported at the joint between the rear θ2-axis link 15 and the front θ2-axis link 17, and the θ-axis attached to the rotating shaft 18a of the DD motor 18. An endless belt (
Below is the rear θ.

An endless belt (referred to as a shaft drive belt) stretched between a pulley 23a attached to the lower part of the intermediate shaft 21 and a pulley 23b attached to the main shaft 19;
(hereinafter referred to as the front side θ and shaft drive belt) 23, and the rear side 0. It is attached to the other end of the shaft link 15, and when in a predetermined state, the front side θ
It consists of a stripper 24 that abuts one end of the biaxial link 16.

Therefore, the rear θ1-axis link 14 and the front θ1-axis link 1
6. Front θ2-axis link 17 and rear θ□-axis link 15
The 6-link mechanism 25 is connected in a rectangular shape, with the adjacent rear side θ, the axis link 14 and the front side θ, and the axis link 16 having vertically alternating swing surfaces, and the adjacent rear side θ. θ2 axis link 15 and front and rear θ.

The axis link 17 similarly has swinging surfaces that are alternated vertically, and since the rear θ1-axis link 14 and the front θ2-axis link 17 swing on the same plane, they have interfering swinging surfaces. Since the θ2 link 15 and the front θ1-axis link 16 also swing on the same plane, they have swing surfaces that interfere with each other.

Further, at least the rear θ2-axis link 15 and the front θ2-axis link 17 are formed in a hollow shape, and have a pulley 22a inside.
22b rear side θ, shaft drive belt 22, pulley 23a,
23b.

A front θ three-axis drive belt 23 is arranged.

Next, the operation of the above configuration will be explained. first.

When extending the link mechanism 25 described above, θ1 axis DD
The motor 12, θ, and shaft DD motor 13 are each driven to rotate inward. As a result of this drive, each link swings, changes into a rectangular linear shape, and is stopped by the stopper 24 just before it stretches and becomes a straight line. At this time, the link mechanism 25 is in its most extended state. In addition, when retracting the link machine 4125, the θ□ axis DD12
and the θ two-axis DD motor 13 may be respectively driven to rotate outward.

- side, θ, when driving the axis DD motor 18, the rear side θ.

When the main shaft 19 rotates via the shaft drive belt 22, the front side θ, and the shaft drive belt 23, and drives the Z-axis drive device 20, the main shaft 19 moves up and down. Furthermore, by appropriately selecting the difference in rotational direction and rotational speed between the θ1-axis DD motor 12 and the θ2-axis DD motor 13, the main shaft 19 can be moved to any position within the plane.

Next, the nodal force applied to the link when the link mechanism 25 is operated will be explained. FIG. 3 functionally shows the link mechanism 25 corresponding to FIG. 10 and FIG. Figure 4, like Figures 12 and 13, shows the nodal force applied to the front θ1-axis link 16 when the θ axis is fixed and the θ2 axis is accelerated or decelerated. Since the front θ2-axis link 17 is not connected to the intermediate portion of the θ1-axis link 16, no bending moment due to the inertial force Fi of the load inertia i is applied. The bending moment applied to the front side θ and the shaft link 17 is:
It is only the moment of reaction force generated by the rotation of the load inertia i. For this reason, the front side θ which is the tip side of the link mechanism 25, the axis link 16 and the front side θ, the axis link 1
The bending moment applied to 7 becomes smaller.

- On the other hand, since the θ-axis DD motor 18 is arranged at the center of the link machine $25, it has small inertia with respect to the operation of the 01-axis and the θ2-axis.

Therefore, by configuring as one or more.

Since the mechanical strength required for the front θ-axis link 16 and the front θ2-axis link 17, which are on the tip side, is reduced and the weight is reduced, the capacity of the θ1-axis DD motor 12 and the θ2-axis DD motor 13 can be reduced. , the operating speed can be improved by increasing acceleration and deceleration. In addition, since there is nothing that interferes with the center of the link mechanism 25, it can be used in all directions (360°).
It is possible to turn around.

Note that the present invention is not limited to the above-described embodiments, and may be configured as described below, that is,
The industrial robot 30 shown in FIG. 5 has a θ3-axis DD motor 3.
1 is placed below the 02-axis DD motor 13 and attached to the frame 11, and this rotating shaft 31a is a hollow-shaped rotating shaft 13a of the θ-axis DD motor 13 and the θ1-axis DD motor 12,
12a and extend upward, and attach pulley 2 to the upper end of this.
The structure in which 2a is attached is different from the above-described embodiment. The operation of the link mechanism 25 is the same as in the above-described embodiment, but if the transmission ratio between the rear θ, 3-axis drive belt 22 and the front θ 3-axis drive belt 23 is 1, θ, the rotation axis 31a of the DD motor 31 The direction of is the direction of 03 $11119. Furthermore, the mass of the θJ-axis DD motor 31 is
This is inertia that does not affect the axis or the θ2 axis.

Therefore, by configuring in this way, the two axes 19
It becomes easier to maintain the posture of θ, axis DD motor 3
Since the mass of 1 does not affect the operation of the link mechanism 25, the operation can be made even faster.

The industrial robot 35 shown in FIG.
6 is attached to the tip of the link mechanism 25 to rotationally drive the Z-axis 19, and the intermediate shaft 21, the rear θ, the shaft drive belt 22, the front θ, and the shaft drive belt 23 are eliminated. This is different from the example. FIG. 7 shows a combination structure of the θ axis DD motor 36 that rotationally drives the Z-axis 19 and the Z-axis drive device 20 that drives the Z-axis 19 up and down.
In the figure, the Z-axis 19 is composed of a ball screw portion 19a and a spline shaft portion 19b. This Z#
2 mounted on the axis link 16 at the front θ, concentric with 19.
The shaft drive device 20 includes a Z-axis drive motor 37 and a Z-axis position detection device 38. The Z-axis drive motor 37 is
A pole nut 37b that engages with the ball screw portion 19a of the Z-axis 19 is attached to the center of the rotor 37a. Also, θ
, the shaft DD motor 36 has two shafts 1 and 1 at the center of the rotating shaft 36a.
A linear bearing 36b that engages with the spline shaft portion 19b of No. 9 is attached. Therefore, when the Z-axis 19 drives the Z-axis drive motor 37, the pole nut 37b
As the pole nut 37b rotates, the ball screw portion 19 engaged with the pole nut 37b moves up and down. At this time, the Z axis 19 is θ at the spline shaft portion 19b, and the axis DD motor 36
Since it is engaged with .theta., it is possible to move up and down regardless of whether or not the shaft DD motor 36 rotates.

Note that the Z-axis drive device 20 is common to other embodiments.

By configuring as above, θ, axis DD motor 3
Since the Z-axis 19 is directly driven from 6, backlash is reduced and the rotation of the Z-axis 19 is more accurate, and a Z-axis drive belt is no longer required, making the link structure simple and reducing weight. The capacity of the shaft DD motor 13 can be reduced and the operation can be made faster. Also, Z axis 1
Since the circumferential drive devices 9 for rotation and elevation are installed together around the Z-axis 19, the torque due to rotational inertia applied to the θ1-axis and 02-axis is appropriately distributed.

The industrial robot 40 shown in FIG. 8 includes a rear θ1-axis link 14, a rear θ2-axis link 15, and
The structure in which the front θ 1-axis link 16, the front θ, and the axial links 17 all have different swing surfaces is different from the embodiment shown in FIG. 2 described above. Note that the rear θ1-axis link 14 is
The rotating shaft 12a of the θ1-axis DD motor 12 is connected via the θ3-axis DD motor 18. The link mechanism 25 with this configuration changes from a rectangular shape to a linear shape because the links do not interfere with each other, and even after becoming linear, the link mechanism 25 changes back to a rectangular shape by exchanging the positions of each link.

Therefore, by configuring it like this.

By exchanging the positions of the links of the link mechanism 25 as described above, it becomes possible to avoid other objects within the swing range of the link mechanism 25 depending on the height thereof.

The industrial robot 45 shown in FIG. 9 is different from the industrial robot 10 shown in FIG. 2 in that the Z-axis 19 is extended in the opposite direction and the industrial robot 45 is installed upside down. The θ, axis DD motor 18 is either installed inside the frame 11 or at the position shown by the two-dot chain line in the figure.

Therefore, with this configuration, since there is no industrial robot main body (including two DD motors) on the work area side, the work becomes easier and the work target can be expanded.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to improve the operating speed and acceleration/deceleration of the link mechanism that constitutes the arm, and to reduce vibration.

Furthermore, the life of the parts that make up the joint can be extended and maintenance can be made easier. Furthermore, each link constituting the link mechanism becomes a weight-bearing member, making it possible to reduce the overall weight and drive force.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the industrial robot of the present invention, Fig. 2 is a front view of the embodiment of the invention, and Fig. 3 is a functional view of the link mechanism of the embodiment of the invention. Explanatory diagram, 4th
The figure is a nodal force vector diagram of one embodiment of the present invention, Figure 5 is a front view showing another embodiment different from Figure 2 of the present invention, and Figure 6 is similar to Figures 2 and 5 of the present invention. FIG. 7 is a sectional view showing an enlarged part of the embodiment shown in FIG. 6, FIG. 8 is a front view showing another different embodiment, and FIG. 8 is a diagram showing FIGS. 2, 5, and 6 of the present invention. FIG. 3 is a front view showing another embodiment different from the above. Fig. 9 is a front view showing another embodiment of the present invention different from Figs. 2, 5, 6, and 8, and Fig. 10 functionally shows the link mechanism of a conventional industrial robot. FIG. 11 is an explanatory diagram functionally showing the link mechanism of a conventional industrial robot, which is different from FIG. 10, and FIG. Vector diagram, FIG. 13 is a nodal force vector diagram of the conventional industrial robot shown in FIG. 11... Frame 12... First direct drive motor 13...
Second direct drive motor 14.15. lfi,
17...Link 18.31.36...Direct drive motor 19...Main shaft 20.
...Driving device 25-...Rin') *JIIt (8733) Agent Patent attorney Yoshiaki Inomata (and 1 other person) $ 1 2 Figures 3 Figure 4 Figure 5 Figure 6 Figure 7 Fig. 3 Kaya 7rgJ Kaya! θ Concave If Flash Figure 12 Figure 13

Claims (8)

[Claims] (1) A frame body having an installation surface, a first direct drive motor and a second direct drive motor concentrically attached to the frame body, a link driven by the first direct drive motor, and a A link mechanism consists of a group of four links, including a link driven by a direct drive motor (2), which are arranged horizontally and are continuous in a rectangular shape that is expandable and retractable, forming an arm, and a link mechanism is installed near the tip of this link mechanism. An industrial robot consisting of a main shaft that can be moved up and down by a drive device and can rotate freely. (2) The industrial robot according to claim 1, wherein each of the adjacent links has different swing surfaces so that they do not interfere with each other. (3) The four links have different rocking surfaces so that the four links do not interfere with each other.
Industrial robots as described in Section. (4) a direct drive motor that is concentric with the first drive motor and the second drive motor and that is attached to one of the links that constitute the link mechanism; The industrial robot according to claim 1, wherein the main shaft is rotationally driven by a belt disposed inside the link. (5) The industrial robot according to claim 1, wherein the main shaft is rotationally driven by a direct drive motor that is concentric with the drive device and attached to one of the links constituting the link mechanism. (6) The industrial robot according to claim 1, wherein the main shaft is rotationally driven by a direct drive motor that is concentric with the first drive motor and the second drive motor and is attached to the frame. (7) The industrial robot according to claim 1, wherein the rotating shaft of the first direct drive motor is hollow, and the rotating shaft of the second direct drive motor passes through it. (8) The industrial use according to claim 6, wherein each of the rotating shafts of the first direct drive motor and the second direct drive motor is hollow, and the rotating shaft of the direct drive motor that rotationally drives the main shaft is passed through. robot.