JPS5973299A - Wrist mechanism of industrial robot, etc. - 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 The present invention relates to a handcuff mechanism that can be used in industrial robots, manipulators, etc., and more particularly to a bendable wrist mechanism with improved positioning accuracy.

Among industrial robots and manipulators, those used especially for welding, sealing, etc. often need to be operated in crowded places, and the front part of the robot with a worker can be flexibly placed at any 41'(41') position. , it is necessary to be able to return the robot and to have a bendable tip so that the application rate of the robot (the ratio of the welding line length or sealing length that can be used by the robot to the total welding line length or sealing length) is high. Therefore, a so-called flexible wrist that can bend freely is required.However, conventional flexible wrists have a lot of play and play due to their mechanism, and are not suitable for work that requires a high degree of precision such as welding work. There was nothing delivered.

Therefore, an object of the present invention is to provide a wrist mechanism for an industrial robot, manipulator, etc. that is flexible and has high positioning accuracy. Next, a case in which the present invention is applied to a wrist mechanism of a welding robot will be described in detail with reference to the accompanying drawings. Here, Figure 1 is a diagram of the entire Molten T80 robot, Figure 2 is a side view showing the robot with a flexible cover attached to its wrist, and Figure 3 is an embodiment of the 951 of the present invention. FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, and FIGS. 5 and 6 are plan views of the entire wrist mechanism according to the second embodiment of the wooden invention. What about the plan view, side view, and Figure 7? 7N6 is a sectional view taken along arrow Is-B, FIG. 418 is a plan sectional view of the hand holding mechanism according to the third embodiment, and FIG. Side i shows the welding work status using the conventional welding Kawaguchi bot's wrist machine!1.
(C1 and (dl) are side views showing the state of welding work by the wrist mechanism according to the invention.

In FIG. 1, the robot body (1) is attached to the base (2) so as to be able to rotate in the direction θ, and the robot body (1)
A first arm (3) is attached to the holder so as to be swingable in the direction θ. The tip of the second arm (4), which is attached to the tip of the first arm (3) so as to be swingable in the direction 03, has a degree of freedom of twisting (turning) in the direction θ4.A flexible wrist mechanism. (5) is attached, and this wrist mechanism (5) has four wrist elements (5a), (5b), (5
C) Connect (5d) with three flat connecting shafts (6a), (6hL
(6C), and the swing angles between each wrist element are θ, 1, C57, θ5, . The angle θ, which is the composite angle of
) is attached with a welding torch (7) in the axial direction. The position of the welding torch when θ is 0 is (7a), and C
51, θ□, θ,.

is equal to 60 degrees in total, and when the torch is combed, the torch is rotated to the position (7b) pointing in a direction 180 degrees opposite to (7a). Therefore, by introducing 04 and θ, it is possible to take any torch posture necessary for welding work.

The welding torch (7) and its control device (8) are connected by a cable (9) that is a bundle of power cables, conduit cables, gas hoses, etc.
9) and wrist eh Side (51) It is desirable to wrap the wrist part with a flexible cover 00 to provide night-retention and dust-proofing effects (see Fig. 2).

The present invention relates to a wrist mechanism (5) having a plurality of bendable joints as described above, and the details thereof will be explained next.

In FIG. 3, which shows the entire wrist mechanism, in the tip (4a) of the second arm, there is a motor M for giving the small needle mechanism (51 a degree of freedom of rotation, and a degree of freedom of swing θ). A motor M is fixed to the arm tip (4a) and a casing (10) coaxially attached to the casing 1.II is a harmonic drive reducer fi.
(I+) (4 marks manufactured by Harmonic Drive System)
The gear +J3 fixed to the rear end of the hollow drive 4*113 meshes with the gear (141) fixed to the output shaft of the motor M. The driven external gear of the harmonic drive reducer is coaxially rotatably attached to the casing (1) via a bearing (1119).
, F times drive shaft +171. The turning drive shaft tt'i forms the base of the entire hand Rt raft ellipse (5),
Turning drive via reducer 01)! 1ilIil! 111 (
17) By rotating the wrist +a <* θ for the whole
Gives turning motion in 4 directions.

On the other hand, the first wrist element (5
a) has a second wrist element (5b) swingable through a connecting shaft (19@) perpendicular to the axis of the manual sowing element; Connecting shaft on the side (191)
) and a third arm 4 with a C-shaped cross section as shown in the fourth opening.
Has a male element (5C), ff, ', 3 wrist part 3
, (5c) further have a fourth wrist element (5d) at the front end thereof via a connecting shaft (19c) so as to be able to swing freely about each connecting shaft. The connecting shaft (19@) and (19
b) refers to the chain block l-(2) installed in the middle of the shaft.
0a), (20b) and the chisel wrapped around them.
It rotates 111 times by the shaft (21a), and the connecting shaft (21a) rotates 111 times.
19b) and (19C'l) are chain sprockets (20C) and (20C'l) attached to their shafts 41 and 1, respectively.
d) and the chain (21b) connecting these rotate at the same speed. Therefore, when the connecting shaft (19a) rotates, the connecting shafts (19b) and (19C) also rotate at the same speed. This is the case where the number of teeth on each chain sprocket is the same. In addition, the connecting shaft (19a) and the first wrist element (5a
) is rotatably attached to the intermediate shaft (2) via a bearing @.
means a chain sprocket (2) with the same number of teeth as the chain sprocket (19a) attached to the shaft ☆11;
1) and (24b) are connected so as to rotate at a constant speed by a chain (c) wrapped around an l+jl chain sprocket. It is desirable that these chain sprocket drives be provided with a tensioner to tension the chain.A bevel gear (2/l The transmission shaft (toward the shaft tip V, 14) is connected to the bearing (support) attached to the first wrist element (5a) and the drive shaft (to the bearing provided in 32).
The spur gear (311) meshes with the gear (2) fixed to the output shaft of the motor 1 on the swinging side.

According to the above explanation, when the motor M rotates, the gear l
141, (sequentially, the drive shaft 0 is rotated at low speed via the harmonic drive reducer wholesale, and the swing drive shaft 0'0 has first to fourth trick elements attached to the tip of the swing drive shaft 0'0. Hand 6 Machine (51 rotates in the direction of 04,
When the eight motors rotate, the intermediate shaft (
2) and connecting shafts (19a), (19b), (19C)
It is understood that rotates at a constant speed.

Next, the oscillating motion between each wrist element will be explained, which is achieved by the harmonic reduction gD 43 interposed between each connection and the following wrist element. That is, bearings C (4
), (The above-mentioned connecting shaft (19a) is pivotally supported through the shaft, and the connecting shaft (19a) has a driving disc (: (7a)) of the harmonic drive reducer (36a) in the middle part thereof.
), and the driving disk (37m) meshes with the fixed mouth external gear (39a) and the driven side external gear (40a) via the flex spline (381). The driven external gear (40a) is a second rotatably attached to the connecting shaft (19a) via the
The first wrist element (5a) and the second wrist element (5b) form a bending joint that can freely swing around the connecting shaft (19a). The first wrist element (5a) is used as the driving side wrist element, and the second hand element (5b) is used as the hand element on the side of the slave 11, and the rotation of the connecting shaft (19m) is controlled by the harmonic drive m.
4i12 (36a), and is transmitted to the second wrist element (5b), which is the subordinate Vh side hand element, and the second
The wrist element (5b) swings around the connecting shaft (19a) at a low speed.

In addition, in the relationship between the second hand 4 elements and the third wrist element, the former is the driving side and the latter is the driven side, and also in the relationship between the third and fourth wrist elements, the jg3 wrist element is the driving side. side, the first wrist element becomes the driven side. The mechanism for transmitting -1 rotation is the same as the above-mentioned rotation transmission from the first wrist element to the second wrist element via a reducer, and the connecting shaft (19b) is connected to the first wrist by the bearing (431 and ω4). It is pivotally supported by the element (5b) and supports the third wrist element (5c) via the bearing (clasp and f4 [9), and the connecting shaft (19
1)) The harmonic drive deceleration m (36
b) has a driving disk (37b) integrally inside the fixed side external gear (39b) fixed to the second wrist element (5b) via a flexspline (38b).
) and the driven external gear (40b) fixed to the third wrist element (5c).

Also, the relationship between the third wrist element (5c) and the fourth wrist element (5d) is similar, and a harmonic drive reducer (36C) is interposed between the connecting shaft (19C) and the fourth wrist element (5d). , %, the rotation of the fast-rotating connecting shaft (19c) is decelerated and transmitted to the first wrist element (5d).

Here, regarding the harmonic drive reducer, the 10th ν1
A brief explanation with reference to 1. I'll keep it. As shown in the figure, the drive disk (support) is elliptical and has multiple rotating rollers (R
) is closely attached to the ring-shaped flexspline made of a material that can be bent during loading, and the flexspline (to) has a plurality of external vJaη on its outer periphery, meshes with the internal teeth (c) formed in a perfect circle inside the fixed external gear mounted on the outside at the long diameter part, and is separated from the short diameter part. External tooth 47) The number of teeth is slightly smaller than that of internal teeth, and the pitch of both is the same.

For example, if the external tooth f471 is 200, the internal tooth (Tsukuda is 202
It's like a sheet. In addition, the flexspline (to) has a driven side external gear (not shown) adjacent to the driving side external gear (to).
o) are in mesh with each other, and the number of internal teeth of the external gear (4α) is adjusted to be the same as the number of external teeth of the flex spline C■.In other words, the internal teeth of the driven external gear and the flex spline The external teeth of the spline sea bream are formed so that the pitch of the external teeth on the flexspline (9) side is slightly wider than the pitch of the internal teeth of the external toothed warship. Therefore, when the driving disk Gn is rotated, the external teeth (4'f) of the flexspline (2) and the internal teeth (fences) of the fixed external gear 09 mesh sequentially, and the driving disk L'3'/ ) rotates once, the flexspline ( ) rotates in the opposite direction to a position delayed by 2M. The external gear on the flexspline and the driven side (4■ has the same number of teeth as Iid, so it follows the rotation of the flexspline υ
The first side external gear (4o) rotates at the same time, so it follows one rotation of the drive disk (material)! 11 side external gear (4 (center is reversed by 2 teeth, reducer 1 is 2 ÷ 200 = '10
It becomes o. In the above explanation, since (2) is fixed and 4 [1 is set to the driven side, +41 is set in the opposite direction to the driving disk (9) /
It will rotate at a deceleration speed of 100, but on the contrary (4■
When fixed, the movable external gear rotates while being decelerated in the same direction as the drive disk 6. Therefore, the motor M rotates; i (-t!
When the connecting shafts (19a) (19bX19-f) are rotated at high speed, for example, looking around the connecting shaft (19ja), if the reduction ratio is '/100, the connecting shaft (193) or 20
When the element (5b) of the driven external gear (40a) and the second hand fixed thereto rotates 0.2 rotations, that is, rotates 72 degrees with respect to the first wrist element (5@). Also, the connecting shaft (19
b) and (19C) rotate the first wrist element (5C
) is the fourth wrist element (5b) with respect to the second wrist element (5b).
d) have approximately the same angle 1 for the third wrist element (5C).
Rotate in the same direction for 1 minute. In the rotation movement after the second wrist element, the rotational speed of the connecting shafts (19b) and (19C) is affected by the rotation angle of the master wrist element, so the final rotation of the fourth wrist element (5d) The swing angle is calculated by correcting the swing angle of these handcuff elements. In this way, the second, third, and fourth wrist elements simultaneously rotate by approximately the same angle, and as shown in FIG.
) the torch (7) attached to the tip is horizontal (7a)
It rotates by θ with respect to the center.

It is desirable to attach the cable (9) connected to such a torch along the axis of the machine as much as possible to avoid interference with the workpiece or the like. Therefore, wooden wrist M1
．． As shown in Figure 4, in the 4th grade, a groove (grooving) that sinks in the axial center direction is provided on the soil surface of each handshake element.
9) Power cable group, conduit cable (51
), housing the cable (9) with built-in gas port I7
, if necessary, the groove (4) is closed by a cover 6). Also, the wrist 171 [5] is a flexible cover for the purpose of soundproofing, dustproofing, etc. as shown in Figure 3). It is desirable to cover it with

In the first embodiment described above, all the connecting shafts are supported on both sides, but in the second embodiment shown in FIGS.
In this embodiment, a cantilevered support mechanism is shown. That is, as shown in FIG. 7, the first wrist bearing s41. ea
Also, the second wrist element (5d) and the first wrist element (5d)
C) are swingably connected by cross roller bearings, and are arranged on one side of the second wrist element 1, and the four-prong receiver ci6+ attached to the first wrist element (5a) and the second hand are connected to the element ( The connecting shaft (19a') pivotally supported by the bearing Gη attached to the harmonic drive reduction mode (36a') has a driving disc (37a) on one integral surface 2, and the driving disc (37a) 37
a) is the first
Fixed external gear (39a') fixed to wrist element (5a)
) and a follower (fil) fixed to the second wrist element (55').
When the connecting shaft (19a'), which is meshed with the external gear (4o;) and has a sprocket (24a') at the shaft end by the chain d, rotates at high speed, this rotation is decelerated by the reducer (36a'). The driven side external gear (40a
') and a second wrist element (5
g) rotates at low speed. The connecting shaft (19a') is connected by a chain (21a') to a connecting shaft (196) connecting the second wrist element (5d') and the third wrist element (5c'), and further connected to the connecting shaft (195'). is connected to a connecting shaft on the distal end side (not shown) by a chain (2tb). The state of connection between the second wrist element (55') and the third wrist element (5J) and the configuration of the harmonic drive reducer (36d') interposed between them are also the same as described above, and will therefore be omitted.

The speed reducer used in the present invention is not limited to the harmonic drive speed reducer described above, but #1 using a planetary gear speed reducer 1, a planetary roller speed reducer, etc. is also nJ type. FIG. 8 shows a partial sectional view of the four-hand gutter when a planetary gear reducer (:46a'' to 36C'') is used. In other words, in FIG.
b'') and the third wrist element (5 ('') are similarly bearings (!
Connected by +9. The connecting shaft (19a'') disposed coaxially with the bearing (to) is connected to the first wrist element (5a
' ) side bearing (11) and the second wrist element (5b'') side bearing (6υ), the connecting shaft (1
The gear (() force engraved in the middle of the second wrist element (5b") is engaged with the planetary gear ((4) rotatably attached to the bottle (0) screwed onto the second wrist element (5b"), gear e
41 is internally engaged with an external gear fixed to the f11 wrist element (52"). Therefore, for example, the first wrist element (52")
When the chain (25") is run and the connecting shaft +In is rotated with the gear 6φ and the external gear (5a') fixed, the gear 6φ and the external gear (
A planetary gear (the circle rotates on its own axis and is decelerated around the connecting shaft (19a'')), and the second wrist element (5b'') rotates at low speed around the divine connection axis (19a''). The connecting shaft (19a") is connected to the chain (21a") so as to rotate in one cycle.
The same applies to the planetary gear (output) that meshes with the third wrist element (5 (")) and the third wrist element (5 (")) rotates at a low speed relative to the first hand four elements (5b") by the rotation of the connecting shaft (19b"). In this way, the rotation of each connecting shaft connected by the chain is decelerated and transmitted to the next wrist element, and each hand knife element swings at approximately the same angle.

In each of the above embodiments, a chain was used as a member for transmitting rotation to the connecting shaft, but it is also possible to replace it with a belt, wire, etc., and the number of teeth of the sprocket that drives such a rotation transmitting member may be changed. are all the same, but by changing the number of teeth or changing the reduction ratio of the reducer connected to the attached connecting shaft, the swing angle between the wrist element on the driving side and the wrist element on the driven side can be changed. It is also possible to change sequentially11
It's Hi.

As described above, the present invention includes one drive puller 11 element and one follower Uu that swings with respect to the drive side wrist element.
A set of wrist joints is formed by the l-J-'i-4' mounting system, and two or more wrist joints are connected to each other so that it can be bent freely, and is used as a wrist mechanism for industrial robots, etc. 1i-J, the driving side hand element and the driven side wrist element are swingably connected to the axes of both wrist elements via a corner connecting shaft, and the connecting shaft and the driven eccentric wrist element are connected to each other. Industrial use characterized by interposing a speed reducer between them to regulate the swing period of the driven side wrist element relative to the driving side hand U element, and connecting adjacent connecting shafts by the rotation transmission part +1. Since this is a hand mechanism for a robot, for example, if the present invention is applied to a hand mechanism for a welding robot, the conventional hand mechanism would have to bend the wrist in multiple stages due to accuracy errors. As shown in Figure 9 (ta+ and (I)), since the iμ contact torch +691 was attached to the wrist at the tip of the arm (69), the height of the obstacle u cta was increased. In some cases, it was not possible to weld the lower part of the barrier [phase], leading to a decrease in the application rate of the robot. However, in the present invention, the wrist is bent in multiple stages, so welding is not possible at the bottom of the barrier [phase], as shown in Fig. 9 (C). It was possible to easily overcome the long barrier υD and perform the Qingsho work, which significantly improved the application rate of the robot.In addition, there was a deceleration 'J between the driving side hand element and the driven side wrist element. Since K7 is inserted through E, any play or backlash in the rotation transmission member is compressed and transmitted to the wrist element on the non-driven side, so it is suitable for wrist mechanisms such as welding robots that require precision positioning of cylindrical degree. It is extremely suitable for application to

[Brief explanation of drawings]

FIG. 1 is a side view of the entire welding robot equipped with a wrist mechanism according to the first embodiment of the present invention, and FIG. 2 is a side view showing a state in which a flexible cover is attached to the tenth part of the robot. FIG. 3 is a plan view of the entire hand mechanism according to the first embodiment of the present invention, and FIG. 4 is a cross section taken along the line A-A in FIG. 3.
, FIGS. 5 and 6 show the hand M according to the second embodiment of the present invention.
A plan view and a side view of the P& structure, If 9ryJ (3) and (bl) are side views showing the welding work status using the wrist mechanism of the conventional welding Kawaguchi bot; FIG. 10 is a side view showing the wrist mechanism according to the invention in a welding work state, and shows the principle of operation of a harmonic drive speed reducer, which is an example of a speed reducer that can be used in the implementation of the present invention. iE
1Ti+ figure. 5 a~5 d, 5 a~5 d, 5 az,
, 5d: , wrist elements 21a, 21b, 21a, 21.
b, 21a", 21b"...Chiko-7 (Rotation transmission part scoop) Applicant: Kobe Steel, Ltd. Representative Patent attorney Takeo Honjo No. 9 (a) (C)

Claims (1)

[Claims] One wrist element on the driving side and one wrist element on the driven side that swings 8 (11) with respect to the driving wrist element form a wrist a joint, and connect two or more wrist joints in sequence. In a hand hammer for an industrial robot, etc., which can be bent freely by the hand, the driving side wrist element and the driven side wrist element are swingable via a connecting shaft perpendicular to the axes of both front elements. A speed reducer is interposed between the connecting shaft and the driven wrist element to regulate the swing angle of the driven wrist element with respect to the driving wrist element, and the adjacent connecting shafts are further connected by a rotation transmission member. A hand σ mechanism for industrial robots, etc., characterized by the following.