JPH0729273B2 - Industrial robot protector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a protection device for preventing an industrial robot such as an arc welding robot from being damaged by interfering with a work or the like during its operation.

[Prior Art] In an industrial robot, especially an arc welding robot, arc welding work is performed by a welding torch at the tip of the robot. At this time, if the welding torch interferes with a work or the like and receives an excessive load, the welding torch will Problems may occur such as bending or damaging the drive system of the wrist system.

As a means to protect the robot from such troubles, insert a fragile thing (for example, Bakelite) in the torch's mounting bracket, and if the robot receives an excessive load when a trouble occurs, fold the mounting bracket to reduce the load. It is being absorbed to protect the parts after the mounting bracket. In addition to the above-mentioned means, protection is also performed by a device called a shock sensor.

However, all of these means are external to the robot, which is not preferable for compact construction of the robot. The protection device has the advantage that it can be built into the robot.

Therefore, the inventor of the present application conventionally has, as shown in FIGS.
A protective device with a built-in robot has been put to practical use in the bevel gear part of the wrist. Here, the S6 axis, which is the final axis of the wrist, and the S5 axis in front of it will be described.

S6 axis drive motor (not shown) is a speed reducer (not shown)
The bevel gear 31 is connected to the bevel gear 31 via a bevel gear 32, a holding plate 33, a metal fitting 34, a rotating shaft 35, and bevel gears 35a and 36, and the rotating shaft 37 is pivotally supported in a wrist frame 38. The rotation about the S6 axis is obtained.

Further, the S5 axis drive motor (not shown) is also connected to the bevel gear 42 via a speed reducer (not shown), and the rotation of the bevel gear 42 passes through the bevel gear 41, the holding plate 40, and the metal fitting 39. By being transmitted to the wrist frame 38, rotation about the S5 axis can be obtained.

As shown in FIG. 5, the protective device for the S6 shaft is configured by rotatably providing the bevel gear 32 with the metal fitting 34 and the pressing plate 33 sandwiched between the bevel gear 32 and the holding plate 33. That is,
The metal fitting 34 is fixed to the rotary shaft 35 by a metal fitting mounting screw 45, the bevel gear 32 is sandwiched between the metal fitting 34 and the holding plate 33, and the holding plate 33 is fixed by the protective device adjusting screw 46.
It is fixed by tightening against. Bevel gear 32
Only when the external force received by the S6 shaft exceeds the frictional force generated by the tightening torque of the screw 46 (when overload is used), the pressure plate 33 and the metal fitting 34 rotate.
The bevel gear 32 does not rotate with respect to the holding plate 33 and the metal fitting 34 in a normal working state.

Similarly, the protective device for the S5 shaft is configured by rotatably providing the bevel gear 41 with the metal fitting 39 and the holding plate 40, as shown in FIGS.
That is, the metal fitting 39 is fixed to the wrist frame 38 by the metal fitting mounting screw 44, the bevel gear 41 is sandwiched between the metal fitting 39 and the holding plate 40, and the holding plate 40 is protected by the protective device adjusting screw 43.
Is fastened and fixed to the metal fitting 39 by. Again, the bevel gear 41 rotates with respect to the holding plate 40 and the metal fitting 39 only when the external force received by the S5 shaft exceeds the frictional force generated by the tightening torque of the screw 43, and normally In this working state, the bevel gear 41 does not rotate with respect to the holding plate 40 and the metal fitting 39.

Now, in the protection device for each of the S5 axis and the S6 axis, a check mechanism is attached to each protection device as described later for the purpose of checking and restoring at the time of protection operation. That is,
In the protective device on the S6 axis side, as shown in FIG. 5, the bevel gear 32, the holding plate 33, and the metal fitting 34 have positioning holes 32a,
The escape hole 33a and the positioning hole 34a are formed. Then, the positioning holes 32a, 34a have the same diameter as a positioning jig described later, the relief hole 33a is formed as a diameter slightly larger than the positioning holes 32a, 34a, these holes 32a ~ 34a are usually coaxial. It is located in.

Also, in the protective device on the S5 axis side, similarly, as shown in FIGS. 5 and 6, the bevel gear 41, the holding plate 40 and the metal fitting 39 are provided with positioning holes 41a, relief holes 40a and positioning holes 39a, respectively. The positioning holes 39a and 41a have the same diameter as the positioning jig described later, and the relief hole 40a is formed to have a diameter slightly larger than the positioning holes 39a and 41a.
~ 41a are usually arranged coaxially.

With the above configuration, when the wrist tip (welding torch etc.) interferes with the work etc. and a large force acts on the S5 axis, the metal fittings
39 rotates integrally with the wrist frame 38, but the bevel gear
41 is stationary while meshing with the bevel gear 42, and the metal fitting 39 and the pressing plate 40 rotate with respect to the bevel gear 41 while sandwiching the bevel gear 41.

In this way, when a force equal to or higher than a certain level set by the protective device adjusting screw 43 is applied, the tip rotates while the drive system (speed reducer or the like) remains stationary, so that the drive system can be protected. It is also possible to protect the robot toe such as the welding torch.

In order to check and confirm the operation of the protective device in this way and restore it, a positioning jig (not shown) is inserted from the relief hole 40a of the holding plate 40, and the positioning hole 41a of the bevel gear 41 and the metal fitting 39 are inserted. Insert it into the positioning hole 39a. At this time, if the protective device is not operating,
Since there is no deviation between the bevel gear 41 and the bevel gear 41, the positioning jig is inserted up to the positioning hole 39a of the metal fitting 39. On the other hand, when the protective device operates, the metal fitting 39 is displaced with respect to the bevel gear 41, so the positioning jig is inserted only up to the positioning hole 41a of the bevel gear 41, and is inserted into the positioning hole 39a of the metal fitting 39. If not, the operation of the protection device is confirmed. Then, when recovering the robot, loosen the screw 43 and attach the bevel gear 41 to the metal fitting 3.
9. The pressing plate 40 is rotated to confirm that the positioning holes 39a and 41a are coaxially arranged by the positioning jig, and then the screw 43 is tightened with a predetermined tightening force.

By the way, in recent years, for the purpose of reducing backlash, cost reduction, etc., there is a tendency toward direct drive, and the inventor of the present application also directly outputs the outputs of the harmonic speed reducers 8 and 12 as shown in FIG. We have developed a mechanism that connects directly to the wrist frames 11a, 11b, the output shaft 13, and the output flange 15.

With this mechanism, as shown in Fig. 7, the S5 axis drive motor
The rotational driving force of 10 is transmitted to the harmonic input shaft 7 of the harmonic reducer 8 via the pulley 9, the timing belt 24, and the pulley 6. The harmonic speed reducer 8 includes a wave generator 8a, a circular spline (S) 8b and a circular spline (D) 8c, and the circular spline (D) 8c is directly connected to the wrist frame 11a. The wrist frame 11a is swingably supported by bearings 5 and 21 with respect to the robot body frame 1 side.

Further, the S6 axis drive motor 16 is built in the wrist frame 11a, and the rotational driving force of this motor 16 is directly transmitted to the harmonic speed reducer 12, and is transmitted from the harmonic speed reducer 12 to the output shaft 13 and the output flange 15. To be done. The output shaft 13 and the output flange 15 are rotatably supported by the wrist frame 11b.

In FIG. 7, reference numeral 3A is a mounting case of the harmonic speed reducer 8, 14 is a striker for restricting rotation of the S6 shaft provided on the outer circumference of the output shaft 13 in the wrist frame 11b.
The reference numeral 14 regulates the rotation end with respect to the rotation of the S6 axis for one rotation or more (here, 400 °) by rotating with a guide (not shown) while spirally sliding. It is a thing. A drum-shaped member 18 is connected to the support shaft of the wrist frame 11a. A cable 25 for transmitting signals and power to the motor 16 and the like in the wrist frame 11a is wound around the outer periphery of the drum-shaped member 18. The cable can be processed according to the swing of the wrist frame 11a. 17 is operated by a striker (not shown) attached to the outer periphery of the drum-shaped member 18.
Limit switches 19 and 20 for limiting the swing of the S5 axis are covers of the main body frame 1.

[Problems to be Solved by the Invention] However, in the wrist portion having the direct connection structure shown in FIG.
Intermediary parts such as the drive system shown in the figure (bevel gear,
Since there are no metal fittings, holding plates, etc.), it is not possible to realize a protection device as shown in FIGS.

Therefore, when a large force acts on the tip of the wrist portion of the direct connection structure shown in FIG. 7, the circular spline (D) 8c of the harmonic speed reducer 8 and the wrist frame 11a slide by the amount of the play of the mounting screw. However, there is a problem that the harmonic speed reducers 8 and 12 themselves are damaged, and once the damage is generated, it is necessary to disassemble a considerably wide part of the robot for repair.

The present invention is intended to solve such problems,
An object of the present invention is to provide a protection device for an industrial robot, which has an easily and compact structure even with a speed reducer direct connection structure and can realize protection and restoration of a drive system at the time of overload.

[Means for Solving the Problems] In order to achieve the above object, a protection device for an industrial robot according to the present invention includes a rotating body to which a fixing portion of a reduction gear connected to a rotating shaft is attached, and the rotating body. A rotatably supported main body frame, the rotating body is adjustable with respect to the main body frame side, and the fixing portion of the speed reducer is provided by a frictional force generated on a contact surface in a direction perpendicular to the rotating shaft. At least one positioning hole is provided which is fixed at the outer peripheral position of the positioning body and can communicate with both the rotating body and the body frame side, and a positioning jig having a shape matching the positioning hole is provided in the positioning hole. By inserting, it is characterized in that the displacement between the rotating body and the body frame side is confirmed and the original position is restored.

[Operation] In the above-mentioned industrial robot protection device of the present invention, when a large force acts on the drive unit from the outside and this force exceeds the frictional force between the rotating body and the main body frame side, deceleration The fixed part of the machine rotates integrally with the robot member that receives external force, causing a gap with the main body frame side,
The drive unit and robot members are protected.

The occurrence of such a protective operation is usually confirmed by whether or not the positioning jig can be inserted into the positioning hole that communicates between the rotating body and the main body frame. In other words, when the protective operation occurs and a displacement occurs between the rotating body and the body frame side, the positioning jig cannot be inserted.
Then, the robot and the protection device are restored by adjusting the positions of the rotating body and the main body frame side so that the positioning jig can be inserted into the positioning hole.

In addition, the position where the rotating body is fixed to the body frame side by the adjustable frictional force is the outer peripheral direction position of the fixed part of the reduction gear which is the direction perpendicular to the rotation transmission path direction, and the frictional force Occurs on the contact surface in the direction perpendicular to the rotation axis, so even if the speed reducer is directly connected, the fixing does not increase the length in the rotation transmission path direction due to the frictional force of the rotating body. Therefore, it is possible to provide a protection device that sufficiently meets the demand for downsizing of the industrial robot. Further, by fixing at the above-mentioned outer peripheral position, it is possible to gather the adjustment portion of the rotating body and the adjustment portion of the fixing portion of the reduction gear in a close place on substantially the same plane, and therefore the adjustment work can be facilitated. it can.

[Embodiment of the Invention] A protective device for an industrial robot according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a main part thereof, and FIG. 2 is a side view showing the main part. 3 and 4 are sectional views showing a normal arrangement state of the positioning holes, and FIG. 4 is a plan view of the rotating body. In the figure, the same reference numerals as those used above indicate the same parts, and a description thereof will be omitted. Further, in this embodiment, as in the case shown in FIG. 7, especially in the case of the speed reducer direct connection structure in which the output of the harmonic speed reducer 8 is directly connected to the wrist frame 11a, S
The protective device around the five axes will be described.

The structure shown in FIG. 7 is provided with a mounting case 3A for the harmonic speed reducer 8. However, in this embodiment, as shown in FIG. Used as 3. A circular spline (S), which is a fixed portion of the harmonic speed reducer 8, is attached to the rotating body 3.
8b is attached by a mounting screw 8d.

As shown in FIGS. 1 and 4, the rotating body 3 is provided with a flange portion 3c for obtaining a predetermined frictional force and a sleeve portion 3e capable of accommodating the harmonic speed reducer 8, and a circular spline (S ) A screw hole 3d into which a mounting screw 8d for mounting 8b is screwed is formed. Further, the flange portion 3c of the rotating body 3 has one positioning hole 3a serving as a reference for checking and restoring the protective operation, and 60 ° to allow the movement of the torque adjusting screw 22 when the rotating body 3 rotates. Elongated holes 3b arranged at three positions are formed.

Further, as shown in FIG. 1, the sleeve 2 is integrally attached to the main body frame 1 by the screw 2b, and the rotating body 3 has the sleeve portion 3e as shown in FIGS. 2 While inserting it on the inner peripheral side, the flange portion 3c is sandwiched between the sleeve 2 and the pressing plate 4, and is tightened by the torque adjusting screw 22 penetrating the elongated hole 3b.
It is rotatably supported with respect to the side. The torque (friction force) between the sleeve 2 (main body frame 1 side) and the rotating body 3 can be adjusted appropriately by the tightening force of the screw 22.

Further, the sleeve 2 on the side of the main body frame 1 is formed with one positioning hole 2a serving as a reference for checking and restoring the protective operation together with the above-described positioning hole 3a. It has the same diameter as the hole 3a, and is normally arranged so as to communicate with both the rotating body 3 and the sleeve 2 as shown in FIG. In addition, a positioning jig (round bar; not shown) having a shape matching these positioning holes 2a, 3a can be inserted into the above-mentioned positioning holes 2a, 3a so as to be inserted at the time of protection operation confirmation and restoration. As shown in FIG. 3, the holding plate 4 is formed with an escape hole 4a.

A female screw (tap; not shown) into which the screw 22 is screwed is formed on the sleeve 2.

With the above configuration, when the wrist tip (welding torch, etc.) interferes with the work etc. and a large force acts on the S5 axis, and a force above a certain level set by the torque adjustment screw 22 acts, The rotating body 3 connected to the fixed portion of the harmonic speed reducer 8 rotates integrally with the wrist frames 11a and 11b, but the main body frame 1 side remains stationary, and the rotating body 3 includes the sleeve 2 and While being caught in the holding plate 4,
The sleeve 2 and the pressing plate 4 are caused to rotate relative to each other. At this time, the torque adjusting screw 22 is
Since it penetrates the elongated hole 3b, it does not hinder the relative rotation of the rotating body 3.

Therefore, since the overload around the S5 axis at the tip of the wrist is absorbed by the relative rotation of the rotating body 3 with respect to the main body frame 1 side,
It is possible to protect the drive system and also protect the robot tip such as the welding torch.

In this embodiment, when the protective device has been checked and confirmed to be restored, the robot cover 19 is removed and then a positioning jig (not shown) is inserted from the escape hole 4a of the holding plate 4 in this embodiment. Then, the rotary body 3 is inserted into the positioning hole 3a and the sleeve 2 into the positioning hole 2a. At this time, if the protective device is not operating, there is no deviation between the rotating body 3 and the sleeve 2, so the positioning jig is inserted up to the positioning hole 2a of the sleeve 2. When is operated, since the rotating body 3 is displaced with respect to the sleeve 2, the positioning jig is inserted only up to the positioning hole 3a of the rotating body 3 and is not inserted into the positioning hole 2a of the sleeve 2. From this, the operation of the protective device is confirmed.

Then, when restoring the robot, the torque adjustment screw
Rotate the rotating body 3 with respect to the sleeve 2 and the pressing plate 4 until the positioning holes 2a and 3a are aligned as shown in FIG. After confirming by the positioning jig that the positioning holes 2a and 3a are coaxially arranged, the robot is restored with a predetermined tightening force for the torque adjusting screw 22 with a torque wrench or the like.

As described above, according to the protection device for the industrial robot of this embodiment, it is possible to realize a device capable of reliably protecting the drive system and the tool at the tip of the robot with relatively few parts, and the positioning hole.
By using 2a, 3a and the positioning jig, it is possible to extremely easily confirm the operation of the protective device and perform accurate recovery work after the operation. Further, by utilizing the rotation of the fixed side (rotating body 3) of the harmonic speed reducer 8, even if the speed reducer is directly connected, the structure can be easily and compactly provided to protect and restore the drive system at the time of overload. It will be realized. Further, as a matter of course, since it is a built-in type protection device, it has a more compact structure than the exterior type protection device.

In the above embodiment, the positioning hole 2a of the sleeve 2 and the positioning hole 3a of the rotating body 3 have the same diameter, but they do not necessarily have the same diameter.

Further, in the above embodiment, the wrist device of the robot, particularly, the protection device around the S5 axis has been described.
It goes without saying that the same can be applied to other rotating parts such as arm systems.

Further, in the above embodiment, the displacement of the rotating body 3 with respect to the main body frame 1 is confirmed manually by using a positioning jig, but in order to detect the relative rotation of the rotating body 3 with respect to the sleeve 2, A limit switch, a proximity switch, or the like may be used to notify the operator or the like of the occurrence of the protective operation by the detection signal thereof, or the operation of the robot may be directly stopped.

[Effects of the Invention] As described in detail above, in the drive unit of the industrial robot, the rotating body to which the fixing portion of the reduction gear connected to the rotating shaft is attached, and the main body frame that rotatably supports the rotating body. And is fixed at the outer peripheral position of the fixing portion of the speed reducer by the frictional force that is adjustable with respect to the main body frame side and that is generated on the contact surface in the direction perpendicular to the rotation axis. Together with a positioning hole that can communicate with both the rotating body and the body frame side,
Since the positioning jig is used to confirm the displacement between the rotating body and the main body frame side and to restore the original position, it is possible to protect and restore the drive system at the time of overload. Further, even if the structure is directly connected to the speed reducer, fixing by the frictional force of the rotating body does not increase the length in the direction of the rotation transmission path, so it is possible to sufficiently meet the demand for downsizing of the industrial robot. it can. Further, since the adjusting portion of the rotating body and the adjusting cylinder portion of the fixing portion of the speed reducer can be gathered in a close place on substantially the same plane, there is an effect that the adjusting work can be facilitated.

[Brief description of drawings]

1 to 4 show a protection device for an industrial robot as an embodiment of the present invention. FIG. 1 is a sectional view showing an essential part thereof, FIG. 2 is a side view showing the essential part, FIG. FIG. 3 is a sectional view showing a normal arrangement state of the positioning holes, FIG. 4 is a plan view of the rotating body, and FIGS. 5 and 6 show a conventional protection device for an industrial robot. Is a cross-sectional view showing the main part thereof, FIG. 6 is a side view showing the main part, and FIG. 7 is a cross-sectional view showing the main part of an industrial robot having a speed reducer direct connection structure. In the figure, 1 ... Main body frame, 2 ... Sleeve, 2a
...... Positioning hole, 2b ...... Screw, 3 ...... Rotating body, 3a ...... Positioning hole, 3b ...... Oval hole, 3c ...... Flange part, 3d ...... Screw hole, 3e ...... Sleeve part, 4 ...... Presser foot Plate, 4a ... escape hole,
5 ... Bearing, 6 ... Pulley, 7 ... Harmonic input shaft, 8 ... Harmonic reducer, 8a ... Wave generator, 8b, 8c ... Circular spline, 8d ...
Mounting screw, 9 ... Pulley, 10 ... S5 axis drive motor, 11
a, 11b …… Wrist frame, 12 …… Harmonic reducer, 1
3 …… Output shaft, 14 …… Rotor control striker, 15 …… Output flange, 16 …… S6 axis drive motor, 17 …… Limit switch, 18 …… Drum member, 19,20 …… Cover, 21
...... Bearing, 22 …… Torque adjusting screw, 24 …… Timing belt, 25 …… Cable.

Claims (1)

[Claims] 1. A drive unit of an industrial robot, comprising: a rotating body to which a fixed portion of a speed reducer connected to a rotating shaft is attached; and a main body frame rotatably supporting the rotating body. Is fixed at the outer peripheral position of the fixed portion of the speed reducer by a frictional force that is adjustable with respect to the main body frame side and is generated on a contact surface in a direction perpendicular to the rotation axis, and By providing at least one positioning hole that can communicate with both the main body frame side and inserting a positioning jig having a shape matching the positioning hole into the positioning hole, the rotating body and the main body frame side are connected. A protective device for an industrial robot, which is capable of confirming the gap and restoring the original position.