JPH0123278B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an industrial articulated robot.

[Conventional technology]

A conventional industrial articulated robot is constructed as shown in FIGS. 1, 2, and 3. That is, as shown in FIGS. 1 and 3, the rotation of the upper arm drive motor 2 converts the nut 3b meshing with the feed screw 3a into a linear movement, and moves the upper arm 1 through the link 4 to the first
It is configured to swing as shown by the arrow in the figure. Further, as shown in FIGS. 2 and 3, the rotation of the forearm drive motor 6 converts the nut 7b meshing with the feed screw 7a into a linear motion, and moves the forearm 5 via the rod 8 in the direction of the arrow shown in FIG. It is configured to swing like this.

FIG. 4 is a diagram showing the wrist drive mechanism of the conventional industrial multi-joint robot. That is, the wrist drive motor 9 is installed at the center of swing of the upper arm 1, and is configured to connect its output shaft to the disc 11 to swing the disc 11. And the rocking motion of the disk 11 is
The rotation is transmitted to the disc 12 by the links 14 and 15 to cause it to swing, the disc 13 to swing by the links 16 and 17, and the wrist 18 to swing up and down. Here, the links 14, 15 and the disc 11,
12 constitutes a parallelogram link, and link 1
6 and 17 and the disks 12 and 13 also constitute a parallelogram link mechanism, so that the posture of the wrist is kept constant regardless of the posture of the upper arm 1 and forearm 5.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional industrial articulated robot, in order to reduce the weight of the upper arm and forearm, lower the inertia force, and further simplify the mechanism on the first axis that supports the upper arm, the wrist drive motor is is mounted on a swivel table, and the drive motor for the upper arm and forearm is rotatably supported at the rear of the swivel table.The rotational movement of this drive motor is decelerated and converted into the linear movement of the feed screw, and the rotational movement of the upper arm and forearm is In the past, the reduction of the load on the drive motor was controlled in place of dynamic motion.

However, in this robot, when driving the upper arm and forearm, there is a problem that the rotation angle of the drive motor is not proportional to the rotation angle of the upper arm or forearm, which complicates coordinate calculation. Furthermore, since it uses a feed screw, it is more prone to wear and has a shorter lifespan than a mechanism that transmits motion using only rolling bearings, and the mechanism is complex, making it difficult to control at high speeds. .

An object of the present invention is to solve the above-mentioned problems of the prior art by simplifying the arm drive mechanism, giving it high rigidity, eliminating play, and increasing the positioning accuracy of the arm mechanism. The purpose is to provide a compact industrial articulated robot with a wide range of range.

[Means for solving problems]

That is, in order to achieve the above object, the present invention has the following features:
a swivel base that rotates around a swivel shaft by power of a drive motor; a first upper arm that is supported on the swivel base so as to be swingable about a first axis; a lever that is swingably supported at the center; a second upper arm that rotatably connects one end to the swinging end of the lever; and the other end of the second upper arm and the first arm.
a forearm that is rotatably connected to the swinging end of the upper arm and constitutes a parallelogram link arm mechanism together with the first upper arm, the lever, and the second upper arm; and a wrist provided at one end of the forearm. and a first reduction gear and a second reduction gear whose outputs are connected to the first shaft of the first upper arm and the first shaft of the lever, respectively, are connected to the axis of the first shaft. A first drive motor that swings the first upper arm and a second drive motor that swings the lever are installed facing each other so that the axis of the first shaft is aligned with the swivel base. The first drive motor and the second drive motor are installed facing each other, and the rotational output of each of the first drive motor and the second drive motor is rotationally coupled to the rotational input of each of the first and second reduction gears. It is.

Further, a wrist drive motor for driving the wrist is installed in a swinging portion of the arm mechanism of the parallelogram link.

Further, a U-shaped frame portion is attached to the upper part of the swivel base, and the first upper arm and the lever are swingably supported on the U-shaped frame portion about the first shaft.

[Effect]

With the above structure, the arm drive mechanism can be simplified, have high rigidity, eliminate play, and have high positioning accuracy of the arm mechanism, and can provide a compact industrial articulated robot with a wide range of motion.

In addition, the wrist drive motor is connected to the swinging portion of the arm mechanism of the parallelogram link, that is, the rotational output of each of the first drive motor and the second drive motor is transmitted through the first reduction gear and the second reduction gear. By installing it on the swinging part of the arm mechanism of the parallelogram link excluding the first shaft part connected to the wrist drive motor, the rotational output of the wrist drive motor can be Since there is no need to connect the wrist via the first shaft, the configuration of the power transmission mechanism for driving the wrist can be simplified, and the mechanism on the first shaft also corresponds to the upper arm and forearm. There are only two drive mechanisms, which can be simplified.

Furthermore, a U-shaped frame part is attached to the upper part of the swivel base, and the first upper arm and the lever are swingably supported on the U-shaped frame part about the first axis. It is possible to increase the movable range for rotational movement of the upper arm and lever, and the rigidity can also be increased by supporting both ends.

〔Example〕

The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 5, FIG. 6, FIG. 7, and FIG. 8 are diagrams showing an embodiment of an industrial articulated robot according to the present invention. That is, 24 is a swivel table installed on the base 35 so as to be rotatable about the vertical axis, and on this vertical axis there is an output shaft of a swivel table drive motor (not shown) fixed inside the base 35. They are connected via a speed reducer (not shown). 19
is a first frame supported by a U-shaped frame 24a attached to the top surface of the swivel base 24 so as to be swingable about O.
The upper arm of the upper arm is fixed via a speed reducer (not shown) to the output shaft of a first upper arm drive motor 21 whose axis is located on the center O of one side of the frame 24a. Reference numeral 25 denotes a lever supported swingably about O on a U-shaped frame 24a attached to the top surface of the swivel base 24, and a forearm whose axis is set on the center O of the other side of this frame 24a. It is fixed to the output shaft of the drive motor 21 via a reduction gear (not shown). 20 has one end attached to the lever 25
As shown in FIG. 8, the second upper arm is rotatably connected to the swinging end of the upper arm by a bearing 44. Reference numeral 22 denotes a forearm having a wrist 33 attached at its tip to which a chuck or the like for holding parts is attached; the rear end is rotatably connected to the other end of the second upper arm 20 by a shaft 42;
It is rotatably connected to the swinging end of the upper arm 19 by a shaft 43. The first upper arm 19 and the second upper arm 20 are arranged in parallel, and the lever 25 and the forearm 22 are arranged in parallel. It forms a joint parallel link mechanism.

However, the driving rotational movement of the first upper arm drive motor 21 is decelerated by the speed reducer and directly causes the first upper arm 19 to swing. In addition, the forearm drive motor 2
3 is decelerated by a speed reducer and directly swings the lever 25, and this swinging of the lever 25 causes the forearm 22 to move through the second upper arm 20 to the lever 25.
oscillate at the same angle as the oscillation of.

7 and 8 are diagrams showing a mechanism for driving the wrist 33. That is, 26a and 26b are wrist drive motors, respectively, and a member 27a is rotatably supported by bearings 38a and 38b at the swinging end of the lever 25 at the connection point where the lever 25 and the second upper arm 20 are rotatably connected. , 27b. A link 28 has one end rotatably connected to point A of the swivel base 24, and the other end rotatably connected to the swing end B of the members 27a and 27b (bar 40 that integrally connects the members 27a and 27b). It is. These levers 25 and links 28 are arranged in parallel,
The rotating base 24 and members 27a and 27b are arranged in parallel to form a parallel link mechanism.

29a and 29b are wrist drive motors 26, respectively.
a, 26b via reduction gears 36a, 36b, and a bearing 39 is attached to the swinging end of the lever 25.
It is rotatably supported by a and 39b.
30a and 30b are the second upper arm 20 and the forearm 2, respectively.
It is a disc that is rotatably supported (concentrically with the shaft 42) at a portion rotatably connected to the shaft 42. 41a,
41b is a disc rotatably supported by the forearm 22 and wrist 33, respectively. 31
a, 31b are disks 29a, 29b and disk 30, respectively.
The links 32a and 32b are links in which the disks 30a and 30b and the disks 41a and 41b are respectively connected in parallel link mechanisms. By the way, in order to swing the wrist 33 in the direction of the arrow shown in FIG. 7, to swing the wrist 33 back and forth (direction perpendicular to the plane of the paper), or to rotate the wrist 33 around the axis, the above-mentioned method is used. Two lines are provided as indicated by the suffixes a and b.

However, the rotation of the output shafts 34a, 34b of the wrist drive motors 26a, 26b is controlled by the speed reducers 36a, 34b.
The discs 29a, 29b rotate through the link 36b, driving the links 31a, 31b. Link 3
The movement of 1a, 31b results in the rotation of the discs 30a, 30b, drives the links 32a, 32b, and swings the wrist 33 in the vertical direction (in the direction of the arrow).
Swing the wrist 33 back and forth or
Rotate 3 around the axis. On the other hand, stator side members 27a, 27b of wrist drive motors 26a, 26b
is a bearing 38a around the swinging end C of the lever 25,
The swinging ends B of these members 27a and 27b are connected to the bar 40 and the link 2.
8, it is swingably attached to the upper part A of the swivel base 24. Here, point O, point A, point B, and point C on the swivel table 24 are in a parallelogram relationship,
A four-bar parallel link mechanism is constructed with OA,,,, as stationary nodes. Also, the disks 29a, 29
b, discs 30a, 30b, links 31a, 31b
each constitute a four-section parallel link mechanism, and the disk 30
a, 30b, discs 41a, 41b, link 32
a and 32b each constitute a four-bar parallel link mechanism. In addition, the above-mentioned links 31a, 31b, 32a,
32b is formed by a flexible link such as a chain, and the discs 29a, 29b, 30a, 30b, 41a, 41
It is clear that the same effects as described above can be obtained even if b is formed by a rotating member such as a sprocket wheel.

With this configuration, even if the second upper arm 20 is moved to change the inclination of the forearm 22 and the positions of the wrist drive motors 26a, 26b are also moved, the wrist drive motors 26a, 26b cannot be driven. Unless the disks 29a, 29b are rotated by
The rotational positions of the discs 41a and 41b are kept constant, and the posture of the wrist 33 is kept constant. That is, the posture of the wrist 33 is kept constant regardless of the postures of the first upper arm 19 and forearm 22 without any special control.

By the way, as for the wrist 33, there are cases in which a mechanism shown in FIG. 9 is attached to the tip of the forearm 22, and cases in which a mechanism shown in FIG. 10 is attached. In the case shown in FIG. 9, the wrist 33 is attached to a lever 45 that is rotatably supported around the center of rotation of the disks 41a and 41b and a swinging end of the lever 45.
Lever 4 that swings in the front-back direction perpendicular to the swing direction of
6, the upper end of the lever 46 and the upper end of the disc 41a are connected by a bar 47, and the upper end of the lever 46 and the upper end of the disc 41b are connected by a lever 48.
It is connected with. However, if the wrist drive motor 26a and the wrist drive motor 26b are driven at the same rotation angle and the discs 41a and 41b are rotated at the same angle, the wrist 33 will rotate at that angle Y as shown in FIG. 9B.
turn in the direction If the wrist drive motor 26a and the wrist drive motor 26b are driven at the same rotation angle in opposite directions to rotate the discs 41a and 41b at the same angle in opposite directions, the wrist 33 will be as shown in FIG. 9B. Swings in the X direction.

In the case of FIG. 10, the wrist 33 is connected to a cylinder 49 that is integral with a disk 41a and rotatably supported by a bearing 51, and is rotatable in the axial direction of the cylinder 49 by a bearing 52. supported by
It is also constituted by a bevel gear fixed to the rear end of the disc 41b and a member 50 to which a bevel gear that meshes is fixed. However, if only the wrist drive motor 26a is rotated, the disk 41a (cylinder 49)
rotates to bend the wrist 33 in the Y direction in FIG. 10, and if only the wrist drive motor 26b is rotated, the disk 41b rotates and the wrist 33 moves through the bevel gear to the direction θ in FIG. Twisted in one direction.

As described above, the motor 21 that drives the first upper arm 19 is installed at the swing center O of the first upper arm 19, and the output shaft of the motor is directly fixed to the first upper arm 19 via the reducer. Furthermore, the motor 23 that drives the lever 25 is also installed at the swing center O of the lever 25, and the output shaft of the motor is directly fixed to the lever 25 via the reducer. Only the corner is rotated, and the motor 23 is also driven by the lever 25.
The swing angle (tilt angle) of the forearm 22 in a parallel relationship with
These components are always in a proportional relationship, which makes coordinate transformation very easy.Furthermore, since it is supported only by bearings, there is less wear and the service life can be extended.

Furthermore, since the wrist drive motors 26a and 26b are each installed at the connection point C between the lever 25 and the first upper arm 20, even if the chuck attached to the wrist is used to hold parts and a load is applied to the wrist, the wrist drive motors 26a and 26b
The weight of the wrist drive motors 26a and 26b can be balanced by the weight of the stator side member 27 of the wrist drive motors 26a and 26b.
Since a and 27b are connected by a parallel link mechanism based on the stationary joint of the swivel base 24, the posture of the wrist 33 can always be kept constant even if the forearm 22 is tilted by the lever 25.

Note that a rotation angle detector such as a rotary encoder is attached to each drive motor to enable feedback control.

〔Effect of the invention〕

As explained above, according to the present invention, the arm drive mechanism can be made simple, have high rigidity, eliminate play, and have high positioning accuracy of the arm mechanism, and have a wide operating range, be compact, and The present invention has a remarkable effect of making it possible to obtain an industrial articulated robot that enables high-speed control and also has great economic effects. In addition, by installing the wrist drive motor in the swinging part of the arm mechanism of the parallelogram link, the configuration of the power transmission mechanism for driving the wrist can be simplified, and the mechanism on the first axis can also be There are only two drive mechanisms corresponding to the upper arm and the forearm, which can be simplified. Furthermore, a U-shaped frame part is attached to the upper part of the swivel base, and the first upper arm and the lever are swingably supported on the U-shaped frame part about the first axis. It is possible to increase the movable range for rotational movement of the upper arm and lever, and the rigidity can also be increased by supporting both ends.

[Brief explanation of drawings]

Figure 1 is a left side view of a conventional industrial articulated robot, Figure 2 is its right side view, and Figure 3 is its first side view.
Figure 2 is a front view, Figure 4 is a front view of Figures 1 to 3.
5 is a side view showing the wrist drive mechanism of the conventional industrial articulated robot shown in the figure; FIG. 5 is an external perspective view showing an embodiment of the industrial articulated robot of the present invention; and FIG. , FIG. 7 is a diagram showing an embodiment of the wrist drive mechanism of the industrial articulated robot shown in FIGS. 5 and 6, and FIG. 8 is a side view of the lever and the second upper arm in FIG. FIG. 9A is a cross-sectional view showing the first wrist mechanism attached to the tip of the forearm shown in FIGS. 5 and 6;
FIG. 9B is a perspective view of the wrist mechanism shown in FIG. 9A, FIG. 10A is a sectional view showing the second wrist mechanism attached to the tip of the forearm shown in FIGS. 5 and 6, and FIG.
0B is a perspective view of the wrist mechanism shown in FIG. 10A. Explanation of symbols: 19...first upper arm, 20...second upper arm, 21...first upper arm drive motor, 22
...Forearm, 23...Forearm drive motor, 24...Swivel base, 25...Lever, 26a, 26b...Wrist drive motor, 27a, 27b...Member, 28...
Link, 29a, 29b, 30a, 30b, 41
a, 41b...disk, 31a, 31b, 32a,
32b...link, 33...wrist.

Claims (1)

[Scope of Claims] 1. A swivel base that rotates around a swivel shaft using the power of a drive motor, a first upper arm supported by the swivel base so as to be swingable about a first axis, and the swivel base. a lever supported swingably about the first shaft, a second upper arm rotatably connected to one end of the swinging end of the lever, and the other end of the second upper arm and the each rotatably connected to the swinging end of the first upper arm;
and a forearm that constitutes a parallelogram link arm mechanism together with the first upper arm, the lever, and the second upper arm, and a wrist provided at one end of the forearm, the first shaft portion of the first upper arm; and a first reduction gear and a second reduction gear each having an output connected to the first shaft portion of the lever are installed facing each other along the axis of the first shaft, and the first upper arm A first drive motor for swinging the lever and a second drive motor for swinging the lever are installed on the swivel base to face each other in alignment with the axis of the first shaft, and the first drive motor motor and second
An industrial articulated robot characterized in that the rotational output of each of the drive motors is rotationally connected to the rotational input of each of the first and second reduction gears. 2. A swivel base that rotates around a swivel shaft using the power of a drive motor, a first upper arm that is swingably supported on the swivel base around a first axis, and a first arm that is supported on the swivel base so as to be swingable about a first axis; a second upper arm rotatably connected to one end of the lever; a second upper arm rotatably connected to the other end of the second upper arm and the first upper arm; Each is rotatably connected to the moving end,
and a forearm that constitutes a parallelogram link arm mechanism together with the first upper arm, the lever, and the second upper arm, and a wrist provided at one end of the forearm, the first shaft portion of the first upper arm; and a first reduction gear and a second reduction gear each having an output connected to the first shaft portion of the lever are installed facing each other along the axis of the first shaft, and the first upper arm A first drive motor for swinging the lever and a second drive motor for swinging the lever are installed on the swivel base to face each other in alignment with the axis of the first shaft, and the first drive motor motor and second
The rotational output of each of the drive motors is rotationally connected to the rotational input of each of the first and second reduction gears, and the wrist drive motor that drives the wrist is connected to the arm mechanism of the parallelogram link. An industrial articulated robot characterized by being installed on a swinging part. 3. A swivel base that rotates around a rotation axis using the power of a drive motor, a U-shaped frame portion attached to the top of the swivel base, and a swivel base that swings around a first axis on the U-shaped frame portion. The first movably supported
The upper arm and the first
a second upper arm rotatably connected to the swinging end of the lever, the other end of the second upper arm and the first
a forearm that is rotatably connected to the swinging end of the upper arm and constitutes a parallelogram link arm mechanism together with the first upper arm, the lever, and the second upper arm; and a wrist provided at one end of the forearm. and a first reduction gear and a second reduction gear whose outputs are connected to the first shaft of the first upper arm and the first shaft of the lever, respectively, are connected to the axis of the first shaft. A first drive motor for swinging the first upper arm and a second drive motor for swinging the lever are installed in the U-shaped frame portion to face each other. The first drive motor and the second drive motor are installed facing each other along the axis of the shaft, and the rotation output of each of the first drive motor and the second drive motor is applied to the rotation input of each of the first reduction gear and the second reduction gear. An industrial articulated robot characterized by rotational connection.