JPS58211877A - Prefabricated 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 The present invention relates to an assembly robot, and is particularly intended to perform precise fitting work.

Conventionally, various types of assembly robots have been used, including Cartesian coordinate robots. Among these, horizontally articulated robots, commonly referred to as SCARA robots, have recently attracted attention for use in precision assembly. This robot is published in Japanese Unexamined Patent Publication No. 55-1127.
The mechanism described in Japanese Patent No. 89 is as follows. To explain the structure and principle, as shown in FIG. A second shaft 411'il: a second arm 5 is rotatably attached to the first arm 3 and held parallel to the first rotating shaft 2. A tool holding shaft 5a is provided at the tip of the second arm 6 so as to be slidable up and down, and, for example, an electric screwdriver or the like is attached to the tip of the tool holding shaft 6a.

With such a structure, high tonality is provided in the vertical direction, while the device can be moved by a relatively large distance in the left-right, front-back, and front-back directions even with a small amount of force. In other words, it is said that it is possible to provide directional selectivity of comb 2 ances.

However, when actual fitting operations are performed, the desired compliance characteristics are often not exhibited. One reason for this is that in order to improve the position indexing accuracy of each joint, it is necessary to minimize backlash, elastic deformation, etc. of the joint, but conversely, by doing this, This results in a loss of flexibility in the front, back, left and right directions.

Furthermore, depending on the location, the first arm 3
is twisted and the tip of the tool is no longer held vertically. On the other hand, if the first arm 3 is made to have a highly rigid structure so as not to be twisted, the frictional load and inertia load on the rotating part will increase, and eventually the flexibility in the left and right front and rear directions will be lost. The above is the conclusion obtained from the results of prototype experiments conducted by the present inventors, and it is an object of the present invention to realize an assembly robot suitable for precision fitting work that does not have these drawbacks.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. FIG. 2 is a diagram showing the overall configuration of the assembly robot of the present invention. Reference numeral 6 denotes a base, and a column 7 is vertically attached to the base 6, and a movable base 8 is attached to the column 7 so as to be adjustable and fixed to an arbitrary height. A bearing unit 9 is attached to this movable base 8,
A first arm 13 is attached to this bearing unit so as to be rotatable around a first shaft 12, and the first arm 13 is connected to a motor 11. It is rotationally driven by a reduction gear 10. A second arm 16 is attached to the tip of the first arm 13 so as to be rotatable about a second shaft 14 . At the tip of the second arm, there is a shaft 16 that slides in the same direction as the column 7, and a screw that is provided parallel to this and engages with a nut (not shown) built into the tip of the second arm. The upper end of this shaft 16 is fixed to an end plate 18, and the lower end is fixed to a part of the rotation unit 21. On the other hand, the upper end of the screw 17 is rotatably attached to the end plate 18,
And motor 20. It is rotationally driven by a reduction gear 19. The lower end of the screw 17 is rotatably mounted and supported by the rotation unit 21. The rotation unit 21 rotates the chuck base 22 around an axis parallel to the axis 16. A chuck 23 is mounted on the chuck base 22 and is opened and closed by appropriate means.

Now, this assembly robot grasps the workpiece 24 and
The operation will be explained by taking as an example a case where a chamfered J125K as shown in FIG. 4 is inserted.

Do not switch, motor 11. By reducer 10 etc., first arm 1
3. The second arm 15 and the like are driven to rotate, and the workpiece 25 is brought near the hole 26.

Next, the screw 17 is driven by the motor 20, and the workpiece 24 is lowered. At this time, as shown in FIG.
When the workpiece 24 comes into contact with the chamfered portion, a reaction force in the direction of arrow X acts on the chuck. On the other hand, according to the above-described configuration, the shaft 16
．． Screw 17. Two-rotation unit 2 at the tip of the second arm 16
1 constitutes one parallel spring mechanism, and the reaction force 26 causes the shaft 16 and the screw 17 to move laterally while holding the workpiece 24 in the vertical direction.

FIG. 4 is a side view of the structure of FIG. 3, and in this figure, the screw 17 is hidden in the shadow of the shaft 16 and cannot be seen. In this way, when the workpiece receives a reaction force from the side of the chuck, the lateral restraining force of the chuck is small, so
As shown in the figure, the workpiece can be freely displaced depending on the condition of the hole.

In this example, a=100 sweets and b=35 sweets.

c = d - φ10, and the elastic displacement is from several μ to several tens
It was 0μ.

Based on the above principle, even if the center of the work 24 and the center of the hole 26 are misaligned, the work 24 can be moved.
It can be fitted into the hole 25 extremely smoothly.

In FIG. 6, two shafts 16a and 1 are used instead of the shaft 16.
6b, and two shafts 16a.

16b and the screw 1 are arranged at positions forming an equilateral triangle, as shown in the cross-sectional view of FIG. Further, the chuck 23a is, for example, a commonly used three-jaw chuck or the like, and has a structure that reliably chucks the workpiece from three directions.

Now, in the case of FIG. 5, the second arm 16a.

16a, 16b and the rotation unit) 21a form a well-known compliance mechanism, which has great rigidity in the vertical direction and can be easily moved in the left and right 9 front and back directions even with a small force. It is. Furthermore, in this case, if a chuck that reliably grips the workpiece from three directions is used as shown in Figure 5, the compliance mechanism will hold the workpiece perfectly vertically when mating is performed. It moves back and forth to the left and right, allowing for smooth mating.

As described above, according to the present invention, the vertical movement mechanism section attached to the tip of the second arm can be provided with compliance characteristics, and the driving section of the first arm and the second arm can be configured to have high rigidity and no backlash. As a result, it is possible to position the workpiece very accurately in a predetermined position. In addition, slight positional displacement is achieved by the compliance mechanism of the vertically moving section, making it possible to achieve extremely precise fitting.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional assembly robot, Fig. 2 is a front view of an assembly robot according to an embodiment of the present invention, and Figs. 3 and 4 are the same main parts explaining the operation of the assembly robot. A partially sectional front view, FIG. 5 is a front view of a rotating unit of another embodiment, and FIG. 6 is a plan view of the same. 12 , , , , 1st axis, 13 , , , , 1st arm, 14... 2nd axis, 15 01 2nd arm,
16.16a. 1e b , , , , shaft , 17 , , , + screw ,
23,23800110. Chuck. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure d Figure 3 Figure 4 Figure 51. figure

Claims (2)

[Claims] (1) A first arm that is rotatable around a first rotation axis held by a base, and a second arm that is held by this first arm and rotates around a second rotation axis that is provided parallel to the first rotation axis. a screw that can be moved up and down in the axial direction by rotation, and a shaft that is provided parallel to the axial direction of this screw and in the same direction as the gripping direction of the workpiece; An assembly robot consisting of a chuck unit that is movable up and down, grips a workpiece, and can be inserted into a predetermined hole. (2) A first arm that is rotatable around a first rotation axis held by the base; and a second arm that is held by the first arm and rotates around a second rotation axis that is provided parallel to the first rotation axis. a possible second arm, a screw that can be moved up and down in the axial direction by rotation, and a second arm that is provided parallel to the axial direction of this screw.
An assembly robot comprising a chuck unit, which has a book shaft, is provided on the second arm so as to be movable up and down, grips a workpiece from three directions, and can be inserted into a predetermined hole.