JPS6377682A - Arm structure of industrial robot - Google Patents

Abstract

(57) [Abstract] 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 arm structure for an industrial robot, and in particular, an arm structure provided at the leading edge of an articulated horizontal arm,
It has a vertical arm shaft that can move up and down and rotate, and various end effectors such as a robot hand and other work tools can be attached to the end of the vertical arm shaft, making it possible to perform multi-mode robot work. The present invention relates to an arm structure for an industrial robot having a structure in which a space is secured for laying wiring and piping for supplying electrical signals, operating power, operating fluid, etc. to the end effector.

[Conventional technology and problems to be solved]

Conventionally, horizontal multi-joint arm robots have a vertical arm shaft that can move up and down and rotate at the leading edge of the horizontal arm, and an end effector can be attached to the end of the vertical arm shaft. The arm structure of robots for commercial use is already well known, but since these known vertical arm shafts incorporate operating mechanisms such as vertical movement and rotation into the tip of the horizontal arm, an end effector is attached to the end of the vertical arm shaft. There is a problem in that insufficient consideration is given to operating power, signal lines, supply routes for working fluid, etc. Nowadays, industrial robots are used not only in general environments but also in aversive atmospheres as work spaces. When using piping lines, it is necessary to take sufficient care to ensure that they do not become an obstacle to the aversive atmosphere, and the operating mechanisms such as vertical movement and rotational movement are designed with high precision and high performance. Therefore, it is necessary to provide an industrial robot that can satisfy these demands. Therefore, the present invention seeks to provide a robot that satisfies such needs.

[Solution]

In view of the above-mentioned objects, the present invention has an arm structure for an industrial robot/nod, which is provided at the tip of a horizontal arm, has a mounting end for a robot work element, and has a vertical arm shaft capable of turning and vertical movement. In the above, the vertical arm shaft has a hollow shaft structure, and is provided with a space for laying piping and wiring to reach the robot work element via the horizontal arm, and has a vertical movement operating mechanism consisting of a feed screw shaft mechanism, and a spline. a first rotary drive mechanism, which is provided within the horizontal arm and is coupled to the vertical motion operating mechanism, and which is provided within the horizontal arm and is connected to the vertical motion operating mechanism; and a second rotary drive mechanism coupled to the swing operation mechanism, whereby the piping and wiring can be connected to the vertical arm. It is possible to supply signals, operating power, operating fluid, etc. to the robot working elements, that is, the end effector, through the interior of the shaft.In addition, the rotational movement and vertical movement of the vertical arm axis, as well as the spring feed mechanism, A rotating mechanism with a spline structure is provided in a coaxial structure or a closely spaced structure, and weight reduction due to the hollow vertical arm shaft makes it possible to improve controllability of both turning and vertical movement. Hereinafter, the present invention will be explained in detail based on examples.

〔Example〕

FIG. 1 is a sectional view of a main part showing a first embodiment of an arm structure for an industrial robot according to the present invention, and FIG. 2 shows a second embodiment of an arm structure for an industrial robot according to the present invention. It is a sectional view of the main part.

First, referring to the first embodiment shown in FIG. 1, a most advanced arm 10 of a horizontal multi-jointed arm of an industrial robot is shown, and a vertical arm shaft 12 is attached to the tip of this arm 10 and is movable up and down. It is mounted so that it can be rotated. As shown in the figure, this vertical arm shaft 12 has a hollow structure in which a hole 14 passing through it in the vertical direction is formed, and this hole 14 is used as a space for laying wiring and piping as described later. Further, the lowermost end 16 of the vertical arm shaft 12 has a flange shape, so that an end effector, that is, a robot hand, other robot working tools, etc. can be attached via a fixing means such as a bolt.

This vertical arm shaft 12 further has at least 82 well-known splines extending vertically on its outer circumferential surface, extending over the stroke length of the vertical movement of the W arm shaft 14, and the splines are formed by drilling a hole at the tip of the arm 10. Bearing hole 1
It is engaged with a spline nut formed in the center hole of a pulley 20 which is rotatably held by a rotary bearing 18 fitted in Oa. Therefore, when the pulley 20 rotates, the rotation is caused by the vertical arm shaft 1 through the spline engagement.
2, and the vertical arm shaft 12 can move up and down relative to the pulley 20. Now, in addition to the above-mentioned structures, the vertical arm shaft 12 supports a bracket 26 via a rotary bearing 24 mounted on a bearing seat formed at the upper end 22.
The outer end 26a of 6 has a cylindrical shape, and a female thread is formed inside. This outer end portion 26a is connected to the arm 1.
0 and inside the cover 40, and the arm 10
The threaded shaft 30 is rotatably supported through a rotary bearing 28 in a bearing hole 10b drilled in the shaft. and,
A pulley 32 is fixed to the lower end of the screw shaft 30.

On the other hand, inside the horizontal arm 10, there is a first drive belt/pulley mechanism 34 for swinging a pulley 32 fixed to a screw shaft 30, and a first drive belt/pulley mechanism 34 for swinging a pulley 20 having the aforementioned spline nut. A second drive belt and pulley mechanism 36 is provided. Also, horizontal arm 1
Wiring and piping 38 extending from the robot body (path shown) pass through the inside of 0, and these wiring and piping 38 are further connected to the vertical arm shaft by using the through hole 14 of the vertical arm shaft 12 as a installation space. The lower end of 12 has been reached. In other words, operating power, operating fluid such as pressurized air, control signals, etc. can be sent to the end effector through the wiring and piping 38.

According to the arm structure of the industrial robot of this embodiment having the above-described configuration, when the screw shaft 30 is rotationally driven via the pulley 32 by the first drive belt/pulley mechanism 34,
Due to the vertical movement of the bracket 26, the vertical arm shaft 12
can be moved up and down, and if the pulley 20 is rotationally driven by the second drive belt/pulley mechanism 36, the vertical arm shaft 12 can be rotated around its axis by spline engagement. It can be done.

What should be noted here is that since the vertical arm shaft 12 has a hollow structure, the weight of the vertical arm shaft 12, which is a load on the first and second drive belt/pulley mechanisms 34, 36, is reduced. Since starting and stopping characteristics are also improved, controllability in vertical movement and turning operations can be ultimately improved. And the wiring as mentioned above,
Since the pipe 38 is laid inside, the vertical arm shaft 12
It is possible to significantly reduce the occurrence of twisting when the cable turns, compared to the conventional external laying structure, and the effect of preventing damage to the wiring and piping 38 is also significant. It is also possible to prevent dust from falling into the disliked space due to the generation of dust.

Referring now to the second embodiment of the invention shown in FIG.
This embodiment is also similar to the first embodiment in that a vertical arm shaft 112 is provided at the tip of the horizontal arm 10 so as to be movable up and down and pivotable. This vertical arm shaft 112 also has a through hole 114 in the center and is used as a space for laying wiring and piping 38. The second embodiment differs from the first embodiment in the mechanism for causing vertical movement and rotation of the vertical arm shaft 112, and this point will be described in detail below.

Now, a male thread is formed on the outer periphery of the upper part of the vertical arm shaft 112, forming a threaded shaft part 112a, and on the other hand, the threaded shaft part 11
A spline portion 112b is formed at the bottom of 2a. The screw shaft portion 112a has a rotary bearing 116 installed in a bearing hole 10b drilled in the arm 10, and a rotary bearing 118 installed at the upper end of a pulley 122, which will be described later.
The pulley 120 is screwed into a female thread formed in the center of a pulley 120 rotatably supported around a vertical axis.

Further, the pulley 122 has a hollow cylindrical body 122a, and the body 122a is rotatably supported by a bearing 124 installed in a bearing hole 10a bored in the arm 10. The vertical arm shaft 1 is attached to the lower end of 122a.
A NAND member 126 is attached, which has a spline nut engraved in the center thereof that meshes with the twelve spline portions 112b. That is, the upper pulley 120 and the lower pulley 122 are arranged so as to be able to rotate relative to each other via the rotary bearing 118. The Boo'J 120 is configured to be rotationally driven by a first drive belt/pulley mechanism 34 provided inside the horizontal arm 10;
In addition, the lower pulley 122 is connected to the second belt/pulley mechanism 3.
It is configured to be rotationally driven by 6.

According to the above configuration, the first drive belt/pulley mechanism 3
4, when the pulley 120 is rotationally driven, the vertical arm shaft 112 is moved up and down by the action of the feed screw mechanism formed by the screw engagement between the female thread of the boot I7120 and the screw shaft portion 112a. At this time, the rotation of the screw shaft portion 112a is prevented by the lower spline portion 112b,
Further, the spline portion 112b itself slides on the spline nut of the nut member 126 and smoothly slides up and down. On the other hand, when the lower pulley 122 is rotationally driven by the second drive belt/boot mechanism 36, the nut member 126 also rotates at the same time.
The engagement of the spline nut with the spline portion 112b of the vertical arm shaft 112 causes the vertical arm shaft 112 to rotate. However, the vertical arm shaft 11
2 turns, the vertical arm shaft 112 moves up and down due to the threaded engagement between the threaded shaft portion 112a and the pulley 120. If such vertical movement is inconvenient, the first drive belt/pulley mechanism 34 is activated.
What is necessary is to rotate the pulley 120 and apply a correction rotation so that the relative rotation with the screw shaft portion 112a becomes zero. Of course, such correction rotation can be performed by a well-known robot controller to the first and second drive belt/pulley mechanisms 34, 36.
By sending control signals to each drive motor in
can be easily achieved. In addition, the vertical arm shaft 112
When it is necessary to provide both vertical movement and rotational movement to the
6 can be operated together, and outputs of both vertical movement and rotational movement can be taken out from the vertical arm shaft 112 and transmitted to the end effector attached to the shaft end 112C. In this embodiment as well, a cover 40 is provided, and a guide post 42 is provided which guides the wiring and piping 38 when they are moved up and down.

In this second embodiment, the vertical movement generating mechanism and the turning movement generating mechanism of the vertical arm shaft 112 are provided on the same axis and separated from each other, and therefore has the advantage that the structure around the vertical arm axis can be made compact. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, as an arm structure in a horizontally articulated industrial robot,
The vertical arm shaft, on which the end effector is attached at the end, has a hollow structure with space for laying wiring and piping, allowing for internal wiring and piping structure to supply operating power, working fluid, control signals, etc. to the end effector. wiring,
This eliminates the inconvenience caused by the conventional arm structure in which piping is installed around the outside of the arm structure, and also has the effect of allowing the robot to be used in an aversive atmosphere.
Moreover, during vertical movement and turning operations, the hollow structure of the vertical arm shaft reduces weight, improves starting and stopping characteristics, and reduces the load on the drive system.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing a first embodiment of the arm structure of an industrial robot according to the present invention, and FIG. 2 is a main part showing a second embodiment of the arm structure of an industrial robot according to the present invention. Partial sectional view. 10...Horizontal arm, 12...Vertical arm axis, 14.
...Through hole, 20...Nand member, 26...Bracket, 26a...Outer end portion, 30...Screw shaft, 34...First drive belt/boot mechanism, 36...・
Second drive belt/boot mechanism, 38... Wiring, piping, 112... Vertical arm shaft, 114... Through hole, 112
a...Screw shaft portion, 112b...Spline portion, 120.122...Pulley, 126...Nut member.

Claims (1)

[Scope of Claims] 1. An arm structure for an industrial robot having a vertical arm shaft which is provided at the tip of a horizontal arm and has a mounting end for a robot working element, and which is capable of turning and vertical movement. The arm shaft has a hollow shaft structure and has a space for laying piping and wiring that connects to the robot work element via the horizontal arm, and also has a vertical movement operating mechanism consisting of a feed screw shaft mechanism, a spline shaft, and its engagement. a first rotary drive mechanism provided within the horizontal arm and coupled to the vertical movement operating mechanism; 1. An arm structure for an industrial robot, comprising: a second rotary drive mechanism coupled to a second rotary drive mechanism. 2. The vertical movement operation mechanism consisting of the feed screw shaft mechanism is:
a nut engaged with the vertical arm shaft via a rotation bearing;
a screw shaft that is screwed into the nut and rotated by the first rotational drive mechanism; 2. The arm structure of an industrial robot according to claim 1, wherein the arm structure includes the engaging nut that engages with the engaging nut and is rotated by the second rotational drive mechanism. 3. The vertical movement operation mechanism consisting of the feed screw shaft mechanism and the rotation operation mechanism include a threaded part and a spline part formed on the vertical arm shaft at a distance from each other, and a screw meshed with the threaded part and the spline part. The industry according to claim 1, wherein the screw nut and the spline nut are rotatably coupled to the first and second rotational drive mechanisms, respectively. robot arm structure.