JPS6156076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a robot wrist used for painting robots and the like.

As shown in FIG. 1, a conventional robot wrist has a structure consisting of a position detection encoder 1, a hydraulic actuator 2, an electric wire and hydraulic hose 3, a spray gun 4, and the like.

For this reason, conventional robot wrists have a large volume and are not suitable for complex work such as painting. Furthermore, since the teaching work in such robots is carried out by a person holding the tip of the wrist, it is not just a matter of downsizing the conventional structure; it is also necessary to provide a mechanism that allows the robot to be moved easily by human power during teaching work. It is necessary.

The present invention solves the above-mentioned drawbacks of conventional robot wrists and, in order to meet new demands, proposes a robot wrist that is small in size and capable of performing teaching operations with light force as shown in Fig. 2. It is.

That is, the present invention connects a plurality of main links in series, each consisting of a tip link, an intermediate movable link, and a fixed link, each having a rotating shaft inside, using a universal joint, and connects every other main link so that the central axis of the main link is connected by two sub-links located in a torsional relationship and installed in different directions, and furthermore, two rods corresponding to the sub-links are connected to the intermediate movable link that connects to the fixed link via a two-way bearing. This wrist for a robot is characterized in that it is installed in the same position as the robot, and is configured to give smooth free movement to the wrist by one rotation movement by a joint mechanism and two swing movements by a link mechanism.

FIGS. 3 and 4 are diagrams showing the operating principles of the robot wrist of the present invention. FIG. 3 is a diagram when the user is standing upright, and FIG. 4 is a diagram when the wrist is tilted due to the movement of the cylinder. Although FIGS. 3 and 4 are shown in a two-dimensional manner for ease of understanding, in reality, 12 and 16 are universal joints, and are designed to move three-dimensionally. 13,1
7 and 18 are universal joints. 7, 8, and 9 are main links, and 10 is a sublink that connects the main links. Also, 6 is a rod. Now, if the rod 6 is slightly stretched and changes from the state shown in Fig. 3 to the state shown in Fig. 4, and the second main link 8 is inclined by α with respect to the first main link 7, then the universal joint
If the positions of the opposite corners of 7 and 18 are appropriately selected and the lengths of the third main link 9 and sub-link 10 are appropriately selected, the third main link 9 will also have a value almost close to α with respect to the second main link 8. Can be tilted. If the number of main links is increased in this way, for example, if the number of moving main links is N, the slope of the tip A point can be increased by N×α. In the case of the present invention, two rods 6 are attached in two directions separated by 90 degrees from the tip point A, and one is used for control in the X direction and one is used for control in the Y direction. Accordingly, the sub-links 10 are similarly attached in two directions, and the point A can move in a substantially spherical space centered on the universal joint 12. In addition, a rotating shaft is included in the main links 7, 8, and 9 in order to apply rotation to point A.

Next, specific embodiments of the present invention are shown in FIGS. 5 to 9.

FIG. 5 is a sectional view of the wrist. A first main link 20 corresponds to the first main link 7 in FIG. 3, and is fixed to the arm of the robot body.
21 is the first universal joint cross part,
The first universal joint 28 (corresponding to the universal joint 12 in FIG. 4) is loosely fitted. 22 is a second main link corresponding to the second main link 8 in FIG. 3, 23 is a second universal joint cross part, and a second universal joint 26 (corresponding to the universal joint 16 in FIG. 4). Fit loosely. 24 is a third main link corresponding to the third main link 9 in FIG. 25 is the third rotating shaft, 26 is the second
Universal joint, 27 is the second rotation axis, 2
8 is a first universal joint, and 29 is a first rotating shaft. 30, 31, 32, 33, and 34 are bearings.

FIG. 6 is a front view of the wrist, and FIG. 7 is a left side view of FIG. 6. 50 is the main link 20 in the X direction,
A pushing rod 51 corresponds to the rod 6 in Fig. 3 that moves the rods 22 and 24, and 51 is a bearing corresponding to the universal joint in Fig. 4 that rotates in two directions, the X direction and the Y direction, by the mechanism shown in Fig. 8. . 52 is a support for the bearing 51, and its upper part is fixed to the second main link 22. 53 is a link plate for the X direction, which corresponds to the sub-link 10 in FIG. 3, and is connected to bearings 54 and 56 at both ends.
54 is a bearing that rotates in two directions like the bearing 51, and corresponds to the universal joint 17 in FIG. 3.
55 is a support, 56 is a bearing corresponding to the universal joint in FIG. 4, and 57 is a support for the bearing 56, which is supported by the first universal joint cross part 21 as shown in FIG. 9. 80 is
The pushing rod 50 is provided at a position rotated by 90 degrees, and the main links 20, 22, 24 are
It is a push rod that moves in the direction. Numeral 81 is a bearing that rotates in two directions as shown in FIG. 8, similar to the bearing 51. 82 is a support of a bearing 81 corresponding to the support 52, and its upper part is fixed to the second main link. 83 is a link plate for the Y direction corresponding to the link plate 53;
84 is a bearing that rotates in two directions like the bearing 81 corresponding to the bearing 54, 85 is a support for 84, 88 is a spherical bearing, 87 is a support for 88,
89 is a bearing, and 86 is a support for 89.

FIG. 8 is a sectional view along the horizontal axis of the universal joint 28 in FIG. 6 of the bidirectional rotating bearing. 101 and 104 are integral parts and are also integrated with the pushing rod 80,
Support 82 is swingably supported. 102 and 1
03 is also an integral part and corresponds to the support 82. 105 is a shaft, 106 is a thrust bearing, 10
7, 108, 109 are radial bearings.

FIG. 9 is a horizontal sectional view of the universal joint 28.

In the structure of the robot wrist described above, rotating 29 rotates 25, pushing and pulling 50 moves the tip in the X direction, pushing and pulling 80 moves the tip in the Y direction, and Even if they move in combination, X, Y
Explain that it moves in the direction of composition.

In Fig. 6, when 50 is pressed, the force is transmitted to 52 via 51, and 22 moves, for example, α in the X (+) direction.
Tilt by a degree. Since 24 is connected to 56 by 53, it is tilted by α (approximation) degree with respect to 22 according to the principle shown in FIGS. 3 and 4. Therefore, by pressing 50, 22 is tilted by α degrees with respect to the base, and 24 is tilted by 2α degrees with respect to the base.

Similarly, if you press 80 in Figure 7, 81
The force moves to 82 through , and 22 moves in the Y (+) direction α
Tilt by a degree. 24 is 88 via 85, 84, 83,
Similarly, according to the principle shown in FIGS. 3 and 4, 24 is tilted by 2α degrees in the Y (+) direction. In other words, by pushing or pulling 50, the tip of the wrist can be directed in the Y direction by pushing or pulling 80 in the X direction.

Regarding the composition of
It will be tilted from horizontal. Therefore, the fulcrum P is 2
Even if 2 is tilted by α degree, it is tilted by α degree while maintaining the same position as when it is relatively horizontal. Therefore, if you press 50, you can also tilt your wrist in the X (+) direction. Also, if you pull 80 in this state, you can move it directly in the Y direction. Furthermore, as shown in Fig. 5, a rotation axis passes through the centers of 20, 22, and 24, and these are connected by a universal joint, so no matter which direction the wrist is tilted, the base 29 remains the same. If you rotate it, you can rotate the tip 25.

As described above, in the present invention, as shown in FIG. 2, a relatively small wrist for a robot can be constructed without attaching hydraulic parts, electrical parts, etc. to the tip. Also, during teaching, it is necessary to hold this wrist directly and move it lightly, but with the wrist of the present invention, the movement of the tip of the wrist is an expanded movement of 50 and 80, and 50 and 80 are directly connected to the cylinder. Since it is connected, if you move it from the opposite direction, it will be decelerated, and even if you move the tip with a small force, it will not reach 5.
Since a large force is generated at 0.80, light teaching work can be performed as a result. Also, since this mechanism is a combination of links, it is possible to create a structure with no bumps, like a gear, by judiciously using bearings, etc. According to this mechanism, by increasing the number of links, the inclination angle can theoretically be increased as much as desired.

In addition, in the present invention, by adding a movable intermediate main link corresponding to the second main link 22, an arbitrary inclination angle can be obtained, and
It can be applied not only to painting robots but also to all types of robots such as welding robots and sealing robots. In addition to being used on the wrist, it can also be transformed into the arm itself.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional wrist for a robot, FIG. 2 is a schematic diagram of a wrist for a robot according to the present invention, FIGS.
The figures are a cross-sectional view, a front view, and a side view of the wrist for a robot according to the present invention, FIG. 8 is a cross-sectional view of a bearing that rotates in two directions, and FIG. 9 is a horizontal cross-sectional view of a universal joint part.

Claims (1)

[Claims] 1 A plurality of main links consisting of a tip link, an intermediate movable link, and a fixed link each having a rotating shaft inside are connected in series with a universal joint, and every other main link is connected in a torsionally aligned manner with the central axis of the main link. Two sub-links located in relation to each other and having different mounting directions are connected, and two rods corresponding to the sub-links are installed in an intermediate movable link that communicates with the fixed link via a two-way bearing, A wrist for a robot, characterized in that smooth free movement is given to the wrist by one rotational movement by a joint mechanism and two swinging movements by a link mechanism.