JPH074791B2 - Industrial robot - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an industrial robot suitable for use as an arc welding robot, a painting robot, etc., and more particularly to an industrial robot with an improved joint structure. Is.

[Prior Art] Generally, in a joint part such as a wrist part of an industrial robot,
As shown in FIG. 4, for example, in order to rotationally drive the arm 1 around the S axis, the arm 1 is connected to a drive motor (drive source) 4 via an output shaft 2 and a speed reducer (eg, harmonic speed reducer) 3. The rotation driving force of the drive motor 4 is connected to the arm 1 through the output shaft 2 after being decelerated by the speed reducer 3. Also, the speed reducer 3
Is housed in a casing 5 fixed to the motor 4 side and connects the output side of the speed reducer 3 and the arm 1 to the output shaft 2
Are supported by the casing 5 via cross roller bearings 6.

In a joint part of such a robot, a limit switch mechanism (rotational position detection mechanism) for detecting and limiting the movement range of the arm 1 is conventionally arranged as shown in FIG.
The outer circumference of the output shaft 2 is provided between the arm 1 and the casing 5. That is, the striker 8 is attached to the arm 1, and the limit switch 7 that comes into contact with the striker 8 to operate is attached to the end surface of the casing 5 through the attachment metal fitting 7a. A spacer 19 is provided on the outer circumference of the output shaft 2 between the arm 1 and the casing 5.

Therefore, when the arm 1 rotates to a predetermined position and the striker 8 comes into contact with the limit switch 7, a contact detection signal is output from the limit switch 7 so that the rotation drive of the arm 1 is stopped. It has become.

[Problems to be Solved by the Invention] However, in the above-described conventional industrial robot, since the limit switch mechanism is arranged between the arm 1 and the casing 5, the output shaft 2 is arranged in the space for arranging the limit switch mechanism. Only need to lengthen axially.

Therefore, the joint structure becomes large and the size of the apparatus becomes large, and the expensive cross roller bearing 6 is used to surely support the output shaft 2 which is long in the axial direction in a cantilever manner, resulting in high cost.

In addition, since the limit switch mechanism is exposed to the outside, for example, in welding robots and painting robots, spatter, burrs, paint, etc. scatter and adhere to the limit switch mechanism, or the limit switch mechanism is damaged and becomes inoperable. There is a risk.

The present invention has been made to solve the above problems, and shortens the axial length of the output shaft while preventing the rotational position detection mechanism from being adversely affected by external obstacles. It is an object of the present invention to provide an industrial robot having a joint part having a compact structure.

[Means for Solving the Problems] In order to achieve the above object, in an industrial robot of the present invention, the arm is connected to a drive source via a speed reducer in order to rotationally drive the arm, and the speed reducer is also provided. In an industrial robot having a joint part having a casing for accommodating a motor, the speed reducer includes an output shaft connected to the arm, a cylinder part that rotates together with the output shaft, and a speed reducer provided in the cylinder part. A reducer body including a fuel supply chamber, a detector for detecting an arm rotation position is provided in the casing outside the tubular portion, and a detection piece for operating the detector is an outer peripheral surface of the tubular portion. And a seal portion that separates the speed reducer main body from the detector and the detection piece inside the casing.

[Operation] In the above-described industrial robot of the present invention, in the casing, there is a seal portion between the tubular portion formed on the output shaft of the speed reducer and the oil supply chamber in the speed reducer, and grease leaks from the oil supply chamber. Therefore, even if a detector for detecting the rotational position of the arm is arranged in the casing near the speed reducer, the detector is not affected by the leakage grease. Therefore, it becomes possible to arrange the detector in the casing, and the detector detects the rotation position of the arm by operating with the detection piece at the outer peripheral portion of the output shaft in the casing. It is not necessary to form the output shaft long because of the rotational position detecting mechanism of the above.

Embodiments of the Invention Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an industrial robot as a first embodiment of the present invention, and FIG. 1 is a sectional view showing the main part thereof, and FIG.
The drawing is a sectional view taken along the line II-II of FIG.

As shown in FIGS. 1 and 2, in the present embodiment, the present invention is applied to the joint portion of an industrial robot (for example, a manipulator such as an arc welding robot) similar to the conventional one shown in FIG. The case will be described. At this joint,
In order to drive the arm 1 to rotate about the S axis, the arm 1
Is connected to a drive motor (drive source) 4 via an output shaft 2A and a speed reducer (for example, a harmonic speed reducer) 3, and the rotational driving force of the drive motor 4 is reduced by the speed reducer 3 and the arm is passed through the output shaft 2A. 1 is transmitted.

In the present embodiment, the output shaft 2A of the speed reducer 3 has a speed reducer housing portion 2a that is coaxially expanded in the radial direction.
Is formed, and the speed reducer 3 itself is housed in the inner peripheral surface 2b of the housing portion 2a. Then, between the output shaft 2A and the speed reducer 3, a needle bearing 9 is provided which is circumscribed on the fixed side (motor side) of the speed reducer 3 and inscribed on the inner peripheral surface of the inner peripheral portion 2b of the output shaft 2A. In addition, the housing 2a of the output shaft 2A
An oil seal (seal portion) 10 is provided between the inner peripheral surface and the oil supply chamber in the speed reducer 3.

Further, the output shaft 2A and the speed reducer 3 are housed in a casing 5A fixed to the motor 4 side, and the output shaft 2A connecting the output side of the speed reducer 3 and the arm 1 is a normal ball bearing by the casing 5A. It is supported via 11, and the arm 1 is arranged very close to the end surface of the casing 5.

In the joint part of such a robot, a limit switch mechanism for detecting the rotational position of the arm 1 is provided on the outer periphery of the housing part 2a of the output shaft 2A in the casing 5A, as shown in FIG. . That is, the striker (detection piece) is placed at an appropriate position on the outer peripheral surface of the housing 2a of the output shaft 2A.
Limit switches (detectors) 12,14 that actuate by contacting each striker 13,15 while 13,15 are attached.
Are mounted at appropriate positions in the casing 5 via mounting brackets 12a and 14a, respectively. Here, the limit switch 12 and the striker 13 are for detecting an operation origin, and the limit switch 14 and the striker 15 are for detecting overtravel (operation limit).

Since the industrial robot as the first embodiment of the present invention is configured as described above, the arm 1 receives the rotational driving force of the drive motor 4 decelerated by the speed reducer 3 through the output shaft 2A and is rotationally driven. It Then, when the striker 13 or 15 comes into contact with the limit switch 12 or 14 as the output shaft 2A (that is, the arm 1) rotates, a contact detection signal is output from each limit switch 12 or 14, and the origin detection or arm 1 detection is performed. Processing such as rotation drive stop is performed.

By the way, in the present embodiment, in the casing 5A, the oil seal 10 is provided between the output shaft 2A side of the speed reducer 3 and the oil supply chamber in the speed reducer to prevent grease from leaking from the oil supply chamber into the casing 5A. As it can be prevented, as shown in Figs. 1 and 2, a limit switch that detects the rotational position of the arm 1
Even if 12, 14 are arranged in the casing 5A near the speed reducer 3,
The limit switches 12 and 14 are not affected by the leakage grease.

Moreover, since the limit switches 12 and 14 can be arranged in the casing 5A and are not exposed to the outside as in the conventional case, adverse effects due to spatter, burr, paint, etc. can be prevented.

Further, the limit switches 12 and 14 operate on the outer peripheral portion of the output shaft 2A in the casing 5A by the detection pieces 13 and 15 to detect the rotational position of the arm 1, so that the rotational position detecting mechanism is arranged as in the conventional case. In order to achieve this, it is not necessary to form the output shaft long, and in this embodiment, the reduction gear 3 is used as the output shaft.
Since the output shaft 2A is configured to be housed in the housing portion 2a of 2A, the axial length of the output shaft 2A can be significantly reduced as compared with the conventional one, and the joint portion of the industrial robot can be made compact.

Further, in this embodiment, the output shaft 2A is shortened, and the output shaft 2A is supported by the inexpensive ball bearing 11 and the needle bearing 9 on both sides, so that the rigidity of the joint is improved. There is also an advantage.

FIG. 3 is a block diagram showing a main part of an industrial robot as a second embodiment of the present invention. In this second embodiment, 5 is shown.
An example is shown in which the present invention is applied to a joint portion for rotationally driving the upper arm and the lower arm of a multi-axis robot having 6 axes or 6 axes. Here, as shown in FIG. 3, the same structure as that in FIGS. 1 and 2 is provided in axial symmetry, and the lower arm 1A is rotationally driven by the left side mechanism, while the lower arm 1A is driven by the right side mechanism. The upper arm (not shown) is rotationally driven via the lever 16 and the link member 17.

With the above-described configuration, the same working effect as that of the above-described first embodiment can be obtained in this second embodiment as well.

As a result, substantially the same effect as in the first embodiment can be obtained in the third embodiment. In the third embodiment, the rotational driving force is applied to the pulley 18 by a belt or the like from a driving source (not shown).
Is transmitted to the speed reducer 3 from the pulley 18.

[Effects of the Invention] As described in detail above, according to the industrial robot of the present invention, the seal portion is provided between the output shaft side of the reduction gear and the oil supply chamber in the reduction gear, and the rotation position of the arm is adjusted. With a very simple configuration in which a detector for detecting and a detecting piece that rotates integrally with the output shaft to operate the detector are provided on the outer periphery of the output shaft in the casing that houses the speed reducer, The effect of being able to greatly reduce the axial length of the output shaft and significantly reduce the size of the joint while preventing the adverse effects of spatter, paint, burrs, etc.

[Brief description of drawings]

FIGS. 1 and 2 show an industrial robot as a first embodiment of the present invention. FIG. 1 is a sectional view showing the main part thereof, and FIG. 2 is a sectional view taken along the line II-II of FIG. FIG. 3 is a block diagram showing a main part of an industrial robot as a second embodiment of the present invention, and FIG. 4 is a main part (joint part) of a conventional industrial robot.
FIG. In the figure, 1 ... Arm, 1A ... Lower arm, 2A ... Output shaft, 2a ... Reduction gear housing part, 2b ... Inner peripheral part, 3 ...
… Reducer, 4 …… Drive motor (drive source), 5A …… Casing, 9 …… Needle bearing, 10 …… Oil seal (seal part), 11 …… Ball bearing, 12 …… Limit switch (detector) , 12a …… Mounting bracket, 13 …… Strike (detection piece), 14 …… Limit switch (detector), 15 …… Strike (detection piece), 16 …… Lever, 17
...... Link member.

Claims (1)

[Claims] 1. An industrial robot having an articulated part having a casing for accommodating the speed reducer, wherein the arm is connected to a drive source via a speed reducer to drive the arm to rotate. An output shaft coupled to the arm, a cylinder portion that rotates together with the output shaft, and a speed reducer main body including a speed reducer oil supply chamber provided in the cylinder portion, and the casing outside the cylinder portion. A detector for detecting an arm rotation position is provided inside, a detection piece for operating the detector is provided on an outer peripheral surface of the cylindrical portion, and the reducer body and the detector are provided inside the casing. An industrial robot characterized in that a seal portion is provided to separate the detection piece and the detection piece.