JPH07108485A - Rotary joint of robot and the like - Google Patents

Abstract

PURPOSE:To provide a rotary joint of robot and the like having an outer bearing at the outer side of a reduction gear, which secures a utility area used to the wiring, the piping, and the like of cables, to the through hole at the center of the reduction gear, and can bear against a high load in the rotating operation. CONSTITUTION:In an industrial machine such as a robot, a rotary part 30 rotating relatively to a fixed part 12 is provided, and when the rotation driving force of the rotary part 30 is transmitted from a driving source M to the rotary part 30 through a hollow reduction gear 20, the through hole 22 of the reduction gear is formed in the communicating area between the upper and the lower utility areas 38 and 14 holding the reduction gear 20 between both areas. Consequently, this rotary joint can be used as a wiring and piping space of cables, and a bearing 16 to exercise a large load supporting force to the external load is provided on the outer periphery of the output element of the hollow reduction gear 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary joint of an industrial robot such as a revolving barrel, an arm joint, a rotary shaft of an industrial machine such as a machine tool, that is, a rotary joint of a robot, and more particularly to a drive source. The present invention relates to a rotary joint using a hollow speed reducer having a cylindrical penetrating region in the center as a speed reducer for reducing the rotational output of the.

[0002]

2. Description of the Related Art A rotation source of a drive source such as an electric motor is decelerated by a speed reducer, and the deceleration rotation output drives a rotation unit to rotate relative to a fixed unit, a rotation unit, a drive motor and a deceleration unit. The structure of a rotary joint provided with a rotary drive mechanism including a machine is widely used, for example, in each joint part of an industrial robot, a rotary shaft of a machine tool, and the like.

On the other hand, in recent years, a planetary gear type speed reducer has been frequently used as a speed reducer for such a rotary joint. This type of speed reducer is formed as an integrated unit type speed reducer that directly outputs a decelerated rotation output by incorporating a deceleration gear mechanism that decelerates the rotation input, and the conventional deceleration that sequentially reduces speed via a multi-stage gear mechanism. Compared with the reduction gear mechanism, it has an advantage that the arrangement space can be significantly reduced.

[0004]

On the other hand, the structure of the rotary joint portion in the industrial robot is such that, while using this type of speed reducer, the speed reducer is located on the axis of the relative rotary axis between the fixed element and the rotary element. Since it is provided, it is not possible to secure a space area that communicates the space area that extends from one end side to the space area that is on the other end side when viewed in the direction of the central axis of the reducer. Crawling, wiring, or pipes or tubes for pressurized air, cooling water, etc. have been configured to pass through the outer peripheral region of the speed reducer. Therefore, the cable is protected by a cable guide or the like so as to prevent the cable core wire from being twisted or broken, and to prevent the cable sheath (outer sheath) from being damaged, or to protect the pipes by supporting them with a support frame. The composition was adopted.

However, using the outer peripheral area of the speed reducer as a space for arranging cables, fluid conduits, etc. in this way hinders downsizing of mechanical parts such as robot elements, and it is not possible to provide a cable guide. In many cases, the rotation range of the rotating element is restricted or reduced. Moreover, in the conventional industrial robot, the load transmitted from the load load of the work or the like through the rotating element is often supported by the bearing means built in the speed reducer, and the built-in bearing having a small bearing diameter is used. In many cases, an excessive load is applied to lead to shortening of the service life, and there is a drawback that a sufficient bearing capacity and service life cannot be exhibited under a high load. here,
Considering the reason why cables or cables must be installed inside the robot body and the outer peripheral area of the rotary joint must be crawled, wiring or piping must be taken into consideration. This is caused by the fact that the utilization space that allows pipes and piping, that is, the utility region is divided into two, and there is no communication region that connects these two to each other.

Therefore, an object of the present invention is to solve the conventional problems in the rotary joints of industrial machines such as industrial robots. Another object of the present invention is to solve the conventional problems by using a hollow speed reducer having an input unit and an output unit as an integrated unit and having a through hole of an appropriate diameter in the central region of the unit. The purpose is to provide a rotary joint for a robot or the like.

[0007]

In view of the above-mentioned object, the present invention provides an industrial machine such as a robot, which is provided with a rotating portion which relatively rotates with respect to a fixed portion, and which uses a rotational driving force of the rotating portion as a driving source. From the above to the rotary unit via the speed reducer, the speed reducer is configured by the hollow speed reducer described above, and the through hole is formed in the communication area of the upper and lower utilization space (utility area) sandwiching the speed reducer, It is possible to use it as a cable, tube, pipe wiring, and piping space, and to provide bearing means on the outer periphery of the output element of the hollow reducer, which exerts a large load bearing force against an external load. .

That is, according to the present invention, in a rotary joint of a robot or the like that decelerates the rotational output of the drive motor and rotates the rotary part around a predetermined rotation axis with respect to the fixed part, the rotary drive of the drive motor is performed. A hollow speed reducer having a hollow cylindrical hole in the center, and a stationary wheel locked to the fixed part, which has an output part that reduces the force to a rotational output around a predetermined axis and transmits it to the rotating part. An external bearing device in which a rotary wheel is locked to the outer periphery of the output part of the hollow speed reducer and a hollow cylindrical hole of the hollow speed reducer are provided so as to communicate utility regions on both axial sides of the hollow speed reducer with each other. There is provided a rotary joint for a robot or the like, which is configured by including a cylindrical wall forming unit that secures a cylindrical region.

[0009]

According to the above-described structure, the rotary joint is provided with a cable, a tube, and a pipe (hereinafter collectively referred to as cables) of the hollow reducer without using protective means such as a cable guide or a tube guide fitting. Wiring and piping are performed by the route through the through hole formed in the central area, so the load on the cables during the rotating operation of the rotating part can be reduced, and the size around the reducer and the rotation element can be reduced. The rotation range can be increased, and at the same time, the speed reducer can exert a large load bearing force against an external load applied to the machine via the external bearing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on the embodiments shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing a configuration of a rotary joint provided between a base of an industrial robot and a swing cylinder as a rotary joint according to an embodiment of the present invention. In FIG. 1, the fixed base 12 of the industrial robot 10 is
It is formed as a cylindrical structural element having a space 14 that forms a utility area that can be used as a route for wiring and piping, and has the structural elements arranged therein. It has a substrate 12a. On the upper surface of the ceiling substrate 12a of the fixed base 12, a large diameter bearing 16,
For example, a well-known cross roller bearing bear is mounted, and the reduction gear 20 rotatably supported by the inner ring of the bearing 16 is mounted. Although not shown in detail in the drawing, the speed reducer 20 includes an input element on the center side, and the input element is firmly fixed to the fixed base 12 via a plurality of bolt screws 32, A deceleration output element is provided in the outer peripheral region of this input element, and the deceleration output element is the bearing 16
It is supported from the outside by a bolt screw 34 and is connected to a robot swivel body 30 which constitutes a rotating element.

In the speed reducer 20 described above, a through hole 22 having a relatively large diameter is formed in the central portion, and in this embodiment, the through hole 22 is defined and formed as a cable insertion passage in the through hole 22. The hollow cylindrical sleeve element 36 has a bottom flange 36a, so that the ceiling substrate 12a of the fixed base 12 is fixed.
It is fastened with screws. Robot swivel body 30
A utility region 38 is also formed in the central portion of the fixed base 12, and the through-passage 22 is formed in the utility region 14 of the fixed base 12.
Is formed in a utility region that communicates with the utility region 38 of the robot swivel body 30. Particularly, in the present embodiment, the cables 40 are wired or piped from the lower utility region 14 to the upper utility region 38 or vice versa. Wiring and piping areas are provided.

Here, the cables 40 enter the lower utility region 14 from the input port 12b formed in a part of the fixed base 12, and the sleeve element 36 inserted into the through hole 22 of the hollow type speed reducer 20. It passes through the interior and reaches the upper utility region 38. Then, it is fixed to the robot swivel body 30, which is a rotating element, using a stopper 42. In other words, the cables 40 do not use any protection means such as a cable guide or various supporting tools,
Wiring and piping are performed from the fixed base 12 side to the swivel body 30 side via the central region of the speed reducer 20, and the swivel body 30 is
Even when the swivel operation is performed around the rotation center of the deceleration output element of the speed reducer 20, the cables 40 are extended along the center line of the swivel, so that the cables 40 are twisted or bent. There is an advantage that the expansion and contraction action of the core wire due to the above is reduced, and damages inside and outside the cables 40 can be prevented as much as possible. Moreover, as described above, the cables 4
Since the protection means for 0 is not required around the speed reducer 20, the entire mechanism can be made compact.

Here, the turning operation of the robot turning cylinder 30 has a construction in which a transmission motor mounted on the turning cylinder 30 itself, for example, a well-known servo motor is used as a drive source M to start the operation. The rotation output of the drive source M is transmitted from the pinion 45 attached to the output shaft 44 of the drive source M to the input gear 48 attached to the input shaft of the speed reducer 20 via the transmission gears 46 and 47 of the reduction gear mechanism. This rotation input is transmitted and this rotation input is applied to the speed reducer 2.
It is decelerated inside 0 and transmitted from the output element to the revolving cylinder 30 as a deceleration output.

At this time, in the robot body, the high load applied from the end effector such as the robot hand to the swing body 30 through the robot wrist and the robot arm is reduced.
However, since the output element of the speed reducer 20 is supported by the external bearing 16 having a large diameter, it is possible to have a large resistance to the load.

Further, as described above, around the speed reducer 20,
Since no protection means for the cables 40 such as a cable guide is provided, the utility regions 14 and 38 can be effectively used together to perform the swinging motion of the swivel body 30, and the rotary motion range is not restricted at all. It has the advantage of not receiving it. Although the above-described embodiment has been described with respect to the configuration of the rotary joint for the swivel cylinder that swivels relative to the fixed base of the industrial robot, the present invention is directed to the swivel cylinder of the industrial robot described above. The rotating joint applied to the robot has been described, but other rotating joints of the robot, for example, the rotating joint of the robot arm that rotates relative to the robot body, and the robot wrist that rotates relative to the robot arm. It can be easily understood that the structure of the present invention is equally applicable to the rotary joints and the like.

Needless to say, the invention is not limited to industrial robots, and can be similarly applied to rotary joints of machine tools, industrial vehicles and the like. As the hollow speed reducer, a commercial speed reducer such as an RV speed reducer manufactured by Teijin Ltd. can be used.

[0017]

As is apparent from the above description, according to the present invention, an industrial machine such as a robot is provided with a rotating portion that rotates relative to a fixed portion, and a rotational driving force of the rotating portion is used as a driving source. From the transmission to the rotating part through the reducer,
The speed reducer is configured by the hollow speed reducer described above, and the through-hole has an upper and lower utilization space (utility area) sandwiching the speed reducer.
Bearings that are formed in the communication area of the hollow speed reducer and can be used as wiring for cables, tubes, pipes, and piping space, and that exert a large load bearing force against the external load on the outer periphery of the output element of the hollow reducer. Since it is a configuration that is provided, it is easy to secure the wiring and piping routes of cables, and wiring and piping can be done without the protection means of cables, so that the structure of the rotating part and the mechanism can be made compact. Since the rotating operation by dragging the cables is not performed, it is possible to expand the rotating range of the rotating portion. Moreover, since the load on the cables due to the twisting and bending associated with the rotation operation of the rotating portion can be reduced to a minimum, the resistance of the cables themselves can be increased and the operational reliability of the rotary joint can be improved. .

Further, since the hollow reducer has its output element rotatably supported by a bearing having a large diameter, it has a sufficiently large external load as compared with a conventional small diameter bearing having a built-in reducer. Therefore, it is possible to obtain a highly reliable and long-life industrial machine that can withstand high loads.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a joint of a turning body of an industrial robot as a rotary joint according to an embodiment of the present invention.

[Explanation of symbols]

 10 ... Industrial robot 12 ... Fixed base 14 ... Space 16 ... Bearing 20 ... Reduction gear 22 ... Through hole 30 ... Swivel barrel 36 ... Sleeve element 38 ... Utility area 40 ... Cables

Claims (1)

[Claims] 1. A rotary joint of a robot or the like that decelerates the rotational output of a drive motor and rotates the rotary part around a predetermined rotational axis with respect to a fixed part. The output of the hollow speed reducer, which has an output part for reducing the rotation output of the hollow speed reducer and transmits it to the rotating part, and a hollow speed reducer having a hollow cylindrical hole in the center part, and a stationary wheel locked to the fixed part. An external bearing device in which a rotary wheel is locked on the outer periphery of the portion, and a cylinder provided in a hollow cylindrical hole of the hollow reducer, which secures a cylindrical region that communicates the utility regions on both axial sides of the hollow reducer with each other. A rotary joint for a robot or the like, characterized in that it comprises a wall forming means.