JPS62246496A - 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] [Industrial Application Field] The present invention relates to an industrial robot, particularly a small wrist
The present invention relates to an industrial robot suitable for improving the operating speed and rigidity of each axis of the wrist.

[Prior Art] As a conventional technology related to the wrist of this type of industrial robot, there is a technology disclosed in Japanese Patent Application Laid-open No. 105463/1983.

In this conventional technology, the output shaft of the wrist is directly driven by a gear.

Incidentally, robots are often used for spot welding in the automobile industry, etc., and a robot for spot welding, which handles heavy objects, requires high rigidity in each axis of one wrist.

In addition, since spot welding has many dots, it is required that the travel time from dot to dot be short, and to meet this requirement, it is necessary to shorten the rise time.

The spot welding itself can be quite rough, but if there are variations in the car body or trouble with the robot body, the robot body needs to be compatible in order to start up the line quickly, and the robot body and wrist High precision is required between each part, including the

On the other hand, in order to drive each axis of the wrist of a robot, attaching a drive source such as a motor directly to the wrist axis makes the wrist heavy and large.

It is difficult to create a robot that can be used in narrow spaces or at high operating speeds.Therefore, it is necessary to transmit power from the back of the wrist using some kind of transmission means, rather than attaching the motor directly to the wrist shaft. It arises.

In spot welding, a wrist with at least three degrees of freedom is required in order for the robot to assume all postures in space. The three axes controlling these three degrees of freedom cannot be parallel to each other in order to avoid overlapping degrees of freedom. It needs to change. In the prior art, such a direction change was performed using a bevel gear.

Normally, when a robot's wrist shaft is driven using a motor as a drive source, it rotates at a fairly high speed, so it must be decelerated. As a means for decelerating the rotation by the motor,
There are cases where bevel gears are used on the low speed side and cases where bevel gears are used on the high speed side.

When using bevel gears on the low speed side, that is, after the reducer,
Since the torque to be transmitted is large, it is necessary to make the bevel gear large to match the torque. Moreover, since the speed is low, it is essential to eliminate the backlash of the bevel gear, and an adjustment mechanism is required for this purpose, which complicates the structure of the wrist.

On the other hand, when used on the high-speed side of a bevel gear, that is, in the front stage of a speed reducer, grease lubrication has a limit to the number of rotations, making it impossible to move the output shaft at high speed.

Furthermore, oil lubrication requires a complicated structure to prevent oil leakage, and there are concerns about reliability regarding oil leakage.

Furthermore, whether the bevel gear is used on the low-speed side or the high-speed side, increasing the number of rotations of the bevel gear causes noise problems.

[Problems to be solved by the invention] In short, in the conventional technology that uses bevel gears to decelerate the rotation of a motor, one
Robots that handle heavy objects have a problem in that their wrists become heavy and large. Also.

The conventional technique requires an adjustment mechanism to remove backlash of the bevel gear, which poses a problem of complicating the structure of the wrist. Furthermore, in the prior art, the torque of the reducer is transmitted to each axis of the wrist via gears, shafts, etc., resulting in a decrease in rigidity.

Another problem is that the operating speed is slow.

An object of the present invention is to solve the problems of the prior art as described above, to make the wrist smaller, simpler, and lighter, and to provide the wrist with greater rigidity, faster operating speed, better precision, and reduced noise. Our goal is to provide industrial robots.

[Means for Solving the Problems] In the present invention, the bending axis is tilted to the rotation axis of the wrist and is rotatably supported. A twisting shaft is tilted and rotatably supported by the bending shaft.

Further, a universal joint for the bending shaft is provided between the bending drive shaft connected to the drive source and the rotating shaft. This universal joint and the bending shaft reducer are connected by a single-wrap transmission member.

Furthermore, a universal simulator for the twist shaft is provided between the twist drive shaft connected to another drive source and the rotating shaft. This universal joint and the twist shaft speed reducer are connected by a wrap-around transmission member.

[Function] As mentioned above, the present invention uses a universal joint as a mechanical element for changing the direction of power of the bending drive shaft and the twisting drive shaft.

There is no need to adjust backlash, and a backlash adjustment mechanism can be omitted. Therefore, one wrist can be made smaller, more flexible, and lighter.

In addition, the direction of the power of the bending drive shaft and the twisting drive shaft is changed by a universal joint, and the input shaft of the bending shaft reducer and the input shaft of the twisting shaft reducer are moved parallel to each other via a wrap-around transmission member. , it becomes possible to transmit the signal to the bending shaft speed reducer and the twist shaft speed reducer. As a result, it becomes possible to extract the output of the reducer as it is as rotational force of each axis of the wrist. Therefore, the rigidity of the five wrists can be the same as the rigidity of the speed reducer, so by using a highly rigid and compact speed reducer, the rigidity of the wrist can be easily increased.

Moreover, since a universal joint is used to change the direction of the power, it is possible to eliminate the decrease in accuracy due to backlash, and the rotational force of each axis of the wrist is directly extracted from the output of the reducer. The accuracy of each axis of the wrist can be improved, and even when each axis of the wrist is rotated at high speed, noise can be reduced.

In the present invention, the bending axis is supported at an angle with respect to the rotation axis that is the center of rotation for bending the wrist, and the twist axis is supported at an angle with respect to this bending axis, so that the bending angle of the universal joint is can be made smaller. This makes it possible to improve the power transmission efficiency of the universal joint and facilitate lubrication. Furthermore, the universal joint uses two cruciform joints so that both ends of the universal joint have a constant velocity, but the intermediate shaft of the cruciform joint has an inconstant velocity.

This inconsistency of the intermediate shaft becomes more pronounced as the bending angle of the universal joint increases, and is considered to be a cause of vibration. In the present invention, the bending axis is tilted with respect to the rotation axis that is the rotation center of bending, and the twist axis is tilted and supported with respect to this bending axis, thereby creating a cruciform joint that constitutes a universal joint. The inconsistency of the intermediate shaft can be alleviated. As a result, the weight of one wrist is reduced, and each axis of the wrist can be rotated at high speed without causing any structural stress, so the operating speed of the wrist can be increased.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 to 4 show one embodiment of the present invention.
The figure is an enlarged cross-sectional view of the wrist portion of the robot, FIG. 2 is an enlarged cross-sectional view of the wrist portion rotated by 180' with respect to FIG. 1, No. 3111 is an external view of the entire industrial robot according to the present invention, FIG. 4 is a longitudinal sectional view of the forearm portion of the robot.

The industrial robot of the embodiment shown in FIG.
Forearm 4 and wrist rotation axis 5, bending axis 6, and twisting axis 7
It has

The rotating body 2 is configured to rotate around a vertical axis 8, thereby allowing the robot to move in the left and right directions.

The upper arm 3 is configured to rotate around an axis 9 that is perpendicular to the axis 8, thereby allowing the robot to move back and forth.

The forearm 4 is configured to rotate around an axis 10 that is orthogonal to the axes 8 and 9, thereby allowing the robot to move in the vertical direction.

The wrist rotation axis 5 is attached so as to be rotatable around the central axis 11 of the forearm 4.

The bending axis 6 is inclined with respect to the rotation axis 5 of the wrist, and is rotatably supported by the rotation axis 5. This bending shaft 6 rotates around an axis 1z that is inclined with respect to the central axis ll of the forearm 4, and performs the action of bending the wrist.

The twist shaft 7 is inclined with respect to the bending shaft 6 and is rotatably supported by the bending shaft 6.

The twisting shaft 7 rotates around a shaft 13 that is inclined with respect to the shaft 12, thereby performing a wrist twisting motion. Various tools are attached to this twisting shaft 7, and various operations are performed using the tools.

As shown in FIG. 4, attached to the rear end of the forearm 4 are a motor 14 for the wrist rotation shaft, a motor 20 for the bending drive shaft, and a motor 26 for the twist drive shaft. . Further, inside the forearm 4, a rotary shaft reduction gear 19, a bending drive shaft 25, and a twisting drive shaft 28 are rotatably supported. The bending drive shaft 25 is formed hollow, and the twisting drive shaft 28 is inserted therein.

As shown in FIG. 4, a pulley 16 is connected from the output shaft 15 of the rotary shaft motor 14 to the rotary shaft reducer 19.
The bending drive motor 20 has power transmitted through the timing belt 17 and the driven pulley 18, and the rotary shaft 5 is rotationally driven via the speed reducer 19.
As shown in FIG. 4, a drive pulley 22 and a timing belt 2 are connected from the output shaft 21 of the
3 and the driven pulley 24, the bending drive shaft 25 rotates.

As shown in FIG. 4, power is directly transmitted from the output shaft 27 of the motor 26 for the twist drive shaft to the twist drive shaft 28, so that the twist drive shaft 28 rotates.

1, 2, and 4 are inside the rotation axis 5 of the wrist.
As shown in the figure, the universal joint 3 around the bending axis
2 and a universal joint 35 around the twist axis are supported. Further, between the flange 37 attached to the bending shaft 6 side and the rotating shaft 5, there is a reducer 41 around the bending shaft,
The twist drive shaft 28 and the intermediate shaft 46 of the twist shaft 7 are rotatably supported.

The input shaft 42 of the speed reducer 41 around the bending axis is formed hollow, and the intermediate shaft 46 is inserted inside the input shaft 42 .

One cross joint of the universal joint 32 around the bending axis is supported on the inclined surface 5' of the rotating shaft 5 via a bearing 33, and the other cross joint is supported on the inner circumferential wall of the rotating shaft 5 with a bearing 33.
It is supported through 4. Also.

This universal joint 32 is connected to the bending drive shaft 25.
The drive pulley 29, the timing belt 30, and the driven pulley 34 are connected to the drive pulley 29, and the direction of the power of the bending drive shaft 25 is changed.

One cross joint of the universal joint 35 around the twist shaft is supported by the inclined surface 5' of the rotating shaft 5 via a bearing 36, and the other cross joint is directly connected to the twist drive shaft 28. The universal joint 35 is adapted to change the direction of the power of the twist drive shaft 28.

A drive pulley 38 is connected to the input shaft 42 of the reducer 41 around the bent shaft from the universal joint 32 around the bent shaft.
The timing belt 39 and the driven pulley 40 are configured to move and transmit power in parallel. The speed reducer 41 decelerates the rotation of the input shaft 42 and directly drives the bending shaft 6 to rotate.

A drive pulley 43 and a timing belt 44 are connected from the universal joint 35 around the twist shaft to the intermediate shaft 46.
and a driven pulley 45 to move the power in parallel and transmit it.

As shown in FIGS. 1, 2, and 4, a casing 47 around the bending shaft 6 is attached to the bending shaft 6. As shown in FIGS. The casing 47 rotatably supports another universal joint 4a around the twist shaft, a speed reducer 53 around the twist shaft, and the twist shaft 7.

One cross joint in the other universal symmetry ind 48 around the twist axis is supported by the casing 47 via a bearing 49, and the other cross joint is directly connected to the intermediate shaft 46. This universal joint 48 is adapted to change the direction of the power of the intermediate shaft 46.

Power is transferred in parallel from the other universal joint 48 around the twist shaft to the input shaft 54 of the reducer 53 around the twist shaft by a driving pulley 50, a timing belt 51, and a driven pulley 52. It is configured as follows. The speed reducer 53 reduces the rotation speed of the input shaft 54 and directly drives the twist shaft 7 to rotate.

In the industrial robot of the above embodiment, each axis of the wrist is driven as follows.

In other words, when the motor 14 for the rotating shaft shown in FIG. 5 is the forearm 4 shown in FIG.
is directly rotationally driven around the central axis 11 of.

Also, if the motor 20 for the 1-bending drive shaft is driven.

As can be seen from Figures 1, 2, and 4, the power is
Output shaft 21 → Drive pulley 22 → Timing belt 23 →
The signal is transmitted from the driven pulley 24 to the bending drive shaft 25.

Next, power is transmitted from this bending drive shaft 25 to a drive pulley 29 → timing belt 30 → driven pulley 31 → universal joint 1-32 around the bending shaft, and the direction of the power is changed by this universal joint 32. Next, the drive pulley 38 is connected from this universal joint 32.
→ Timing belt 39 → Driven pulley 40 → Power is transmitted to the input shaft 42 of a reducer 41 around the bending shaft, and this reducer 41 directly drives the bending shaft 6 to rotate around the inclined shaft 12 shown in FIG. be done.

Further, when the motor 26 around the twist shaft is driven, the power is transmitted from the output shaft 27 to the twist drive shaft 28, as can be seen from FIGS. 1, 2, and 4. Then, power is transmitted from this twist drive shaft 28 to a universal joint 35 around the twist shaft, and the direction of the power is changed. Next, from the universal joint 35 to the driving pulley 43 → the timing belt 44 → the driven pulley 45 →
Power is transmitted to the intermediate shaft 46. Furthermore, the intermediate shaft 4
6, the power is transmitted to another universal joint 48 on the circumference of the torsion shaft, and this universal joint 48 changes the direction of the power again. Subsequently, power is transmitted from the universal joint 48 to the drive pulley 50 → the timing belt 51 → the swinging pulley 52 → the input shaft 54 of the reducer 53 around the twist shaft, and the reducer 53 moves the twist shaft 7 to the third It is driven directly in rotation around an axis 13 which is inclined with respect to the axis 12 shown.

Therefore, in this embodiment, universal joints 32, 35, 48 are used as mechanical elements for changing the direction of the power of the bending drive shaft 25 and the twisting drive shaft 28, so that
An adjustment mechanism for adjusting backlash can be omitted.

Furthermore, the rotary shaft 5 is directly rotated by the speed reducer 19. Furthermore, the direction of the power of the bending drive shaft 25 is changed by the universal joint 32, and the power is transmitted to the input shaft 42 of the reducer 41 around the bending shaft by a winding transmission member formed by a drive pulley 38, a timing belt 39, and a driven pulley 40. , and the bending shaft 6 is directly rotated by the output taken out from the speed reducer 41. Further, the direction of the power of the twist drive shaft 28 is changed by the universal joint 35, and the power is transferred parallel to the intermediate shaft 46 via a winding transmission member formed by a drive pulley 43, a timing belt 44, and a driven pulley 45. The power output from the intermediate shaft 46 is changed direction again by another universal joint 48, and the power is transferred to the drive pulley 5.
0, a timing belt 51, and a driven pulley 52, the transmission member moves parallel to the input shaft 54 of the reducer 53 around the twist shaft, and the output taken from this reducer 53 directly rotates the twist shaft 7. I have to.

As a result, the stiffness of the wrist can be regarded as the stiffness of the reducer 19°41.53.

By selecting and using a compact and highly rigid reducer 19, 41, 53, the rigidity of one wrist can be easily increased.

In addition, a universal joint 32. is used to change the direction of power.
35.48, it is possible to eliminate the decrease in accuracy due to pack lash, and the rotational force of each axis of the wrist is taken directly from the reducer 19.41.53. The accuracy of the rotation can be improved, and noise can be significantly reduced even when each axis of the wrist is rotated at high speed.

Furthermore, by supporting the bending shaft 6 at an angle with respect to the rotating shaft 5, the bending angle of the universal joints 32, 35 can be made small. .

The bending angle of the universal joint 48 can be reduced. As a result, the universal joint 32
．． 35.48 power transmission efficiency can be improved and lubrication becomes easier. This makes it possible to alleviate the inconsistency of the intermediate shaft connecting the two cross joints in each universal joint 32, 35, 48.

As a result, vibrations can be reduced, each axis of the wrist can be rotated at high speed, and the operating speed of the wrist can therefore be increased.

In addition, in this embodiment, power is transmitted from the universal joint 32 around the bending shaft to the input shaft 42 of the reducer 41 via a transmission member, so that the universal joint 32 can be freely arranged. degree and thus the axial dimension of the wrist can be shortened.

Furthermore, by arranging two universal joints around the twist shaft, and connecting the universal joint 48 and the input shaft 54 of the reducer 53 around the twist shaft by a wrapping transmission member, the twist shaft 7 and the twist drive shaft are connected. 28 and axis 13
can be made so that they intersect at one point. This results in
The control program can be simplified, and the operating speed can therefore be further increased.

Next, FIG. 5 shows another embodiment of the present invention, and is an enlarged longitudinal sectional view of the wrist portion.

In this embodiment, the twist drive shaft 55 is formed long, and the tip of the twist drive shaft 55 is supported inside the rotation shaft 5 of the wrist via a bearing 56.

Furthermore, a universal stain intro 0 around the twist axis is attached to the inner circumferential wall of the rotating shaft 5 of one wrist.

One cross joint of the universal joint 60 is
It is connected to the twist drive shaft 55 by a winding transmission member including a drive pulley 57, a timing belt 58, and a driven pulley 59. The other cross joint of the universal joint 60 is an intermediate shaft 46 that transmits power to the twist shaft 7.
is directly connected to.

Therefore, in this embodiment, from the twist drive shaft 55 to the drive pulley 57 → the timing belt 58 → the driven pulley 59 →
Power is transmitted to the universal joint 60, the direction of the power is changed by the universal joint 60, and the power is transmitted to the intermediate shaft 46.

Regarding the operation of the other configuration 2 of the embodiment shown in FIG. 5,
This is similar to the embodiment shown in FIGS. 1 to 4 above.

In addition, in the present invention, the wrapped transmission member is not limited to a timing belt stretched between a pair of pulleys and one pulley.
With a pair of sprocket wheels.

A chain may be used, or a silent chain may be used for the chain.

[Effects of the Invention] According to the present invention described above, a bending axis is tilted and rotatably supported on the rotation axis of one wrist, and a twisting axis is tilted and rotatably supported on the bending axis. A universal joint around the bending shaft is provided between the drive shaft and the rotary shaft, and this universal joint and the reducer of the bending shaft are connected by a winding transmission member. A universal joint around the shaft is provided, and this universal joint and the reducer of the twist shaft are connected by a wrap-around transmission member. Since a universal joint is used, there is no need to adjust the backlash, and a backlash adjustment mechanism can be omitted, which has the effect of making one wrist smaller, simpler, and lighter.

Further, according to the present invention, the direction of the power of the 1 bending drive shaft and the twisting drive shaft is converted by the universal joint, and the input shaft of the bending shaft reducer and the input of the twisting shaft reducer are inputted via the 1 wrapping transmission member. The result can be moved parallel to the axis and transmitted to the bending axis reducer and the twisting axis reducer,
The output of the reducer can be directly extracted as the rotational force of each axis of the wrist, and the rigidity of the wrist can be treated as the rigidity of the reducer itself, so by using a highly rigid and compact reducer, the wrist This has the effect of easily increasing rigidity.

Furthermore, according to the present invention, since a universal joint is used to change the direction of power, it is possible to eliminate the decrease in accuracy caused by part crushing, and the rotational force of each axis of the wrist can be directly extracted from the output of the reducer °. This combination has the effect of improving the precision of each axis of the wrist, and has the effect of reducing noise even when each axis of the wrist rotates at high speed.

Moreover, according to the present invention, the bending axis is supported at an angle with respect to the rotation axis that is the center of rotation for bending the wrist, and the twisting axis is supported at an angle with respect to this bending axis, thereby creating a universal joint. This makes it possible to reduce the bending angle of the universal joint, which improves the power transmission efficiency of the universal joint and facilitates lubrication, which reduces the weight of the wrist and reduces the structural impact of each axis of the wrist. Since it can be rotated easily and at high speed, it has the effect of increasing the operating speed of the two wrists.

[Brief explanation of drawings]

Figures 1 to 4 show one embodiment of the present invention.
The figure is an enlarged cross-sectional view of the robot's wrist. Fig. 2 is an enlarged cross-sectional view of the wrist portion rotated by 1800 degrees with respect to Fig. 1, Fig. 3 is an external view of the entire industrial robot according to the present invention, and Fig. 4 is a vertical cross-section of the forearm portion of the robot. FIG. 5 shows another embodiment of the present invention, and is an enlarged longitudinal sectional view of the wrist portion. 4... Forearm, 5... Wrist rotation axis, 6... Bending axis, 7... Twisting axis, 11... Central axis of forearm, 12
...Axis inclined with respect to the central axis 11, 13...Axis 1
Axis tilted relative to 2. 14...Motor for the rotating shaft, 19...Reducer for the rotating shaft. 20... Motor for bending drive shaft, 22... Drive pulley, 23... Timing belt, 24... Driven pulley, 25... Bending drive shaft, 26... Motor for twisting drive shaft , 28... Twisting drive shaft, 29... Drive pulley, 30... Timing belt, 31... Driven pulley, 32... Universal joint for bending shaft.
35...Universal joint for twist shaft, 38
... Drive pulley, 39 ... Timing belt, 40
... Driven pulley, 41 ... Reduction gear for bending shaft, 42
...Input shaft of reducer 41, 43...Drive pulley, 4
4...Timing belt, 45...Driven pulley, 4
6... Intermediate shaft, 48... Other universal joint for twist shaft, 50... Drive pulley, 51... Timing belt, 52... Driven pulley, 53... For twist shaft Reducer, 54...Input shaft of reducer 53, 5
5... Twist drive shaft, 57... Drive pulley. 58...Timing belt, 59...Driven pulley,
60...Universal joint for twist shaft.

Claims (1)

[Claims] 1. A bending shaft is tilted and rotatably supported on the rotation axis of the wrist, a twisting shaft is tilted and rotatably supported on the bending shaft, and the bending drive shaft and the rotation shaft are tilted and rotatably supported. A universal joint for the bending shaft is provided in between, the universal joint and the reducer for the bending shaft are connected by a winding transmission member, and a universal joint for the twisting shaft is provided between the twist drive shaft and the rotating shaft, This industrial robot is characterized by connecting this universal joint and a twist shaft speed reducer with a winding transmission member. 2. In claim 1, an intermediate shaft is provided between the twist shaft universal joint and the twist shaft reducer, another universal joint is connected to this intermediate shaft, and this universal joint and An industrial robot characterized by having a twist shaft speed reducer connected by a winding transmission member. 3. The industrial robot according to claim 1 or 2, characterized in that the winding transmission member is constituted by a pair of pulleys and a timing belt stretched between both pulleys.