JPS6116596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot, and more particularly to an improvement in an industrial robot that grasps and transports an object with a robot hand provided at the tip of an arm system.

In the following description, the horizontal movement of the robot hand in rotation with respect to the robot body is referred to as θ (sheeter) movement. Furthermore, the movement of the robot hand linearly approaching (retreating) or moving away from (advance) the robot body along a horizontal path is called x (x) movement. Further, the linear movement of the robot hand along a horizontal path orthogonal to this x movement is called y movement. Furthermore, the movement of the robot hand in a straight line up and down along a vertical path with respect to the robot body is called z (z) movement.

Industrial robots are required to have various performances, but the main ones are that they do not take up much horizontal space, that there is little risk to workers, and that their posture is stable during operation. It is easy to design how to precisely control the operation, and it is lightweight, sturdy, and can operate at high speed.

Although various types of industrial robots have been developed and put into practical use in the past, none have had all of the above-mentioned performances.

In view of this situation, the present inventors have already proposed an industrial robot that has both the above-mentioned performances. The proposed robot is composed of a control system and an arm system, and the control system has a control motor for x and z movement, more preferably for θ movement, and is housed all together in a base case, and the drive system has It has two shafts each operatively connected to the z-movement control motor and a nut that fits onto these shafts, and is housed in an upright case that stands on the base case, and the arm system is connected to the above nuts. It has a triangular structure consisting of two arms connected to. Driven by the x-movement control motor, the above triangle transforms and the robot hand moves x, and driven by the z-movement control motor, the above triangle moves up and down in parallel, causing the robot hand to move z, and θ Driven by the movement control motor, the above triangle turns and the robot hand moves by θ.

Although this industrial robot is very well-balanced and has all of the above-mentioned performances, it was discovered that there are points that should be further improved in its x-movement. That is, the accuracy of the movement changes depending on the position of the robot hand in the x direction.

As mentioned above, for the proposed robot,
The control motor for x movement is housed in the base case,
This control motor is transmitted to the arm system via the drive system, and the triangle is transformed into a robot hand x.
It has a structure that allows it to be moved. Therefore, the moving speed of the robot hand is high in the area near the robot, and as the robot hand moves forward, the moving speed gradually decreases. That is, when the rotation angle of the control motor is used as a reference, for the same rotation angle, the distance that the robot hand moves is large in an area close to the robot, and the distance that the robot hand moves is small in an area that is far away. By the way, in so-called numerical control of robots and the like, the unit rotation speed (corresponding to the rotation angle) of the control motor is used as the minimum setting standard. Therefore, the above-mentioned situation means that the magnification of this minimum setting standard changes depending on the position in the x direction, which leads to fluctuations in the operating accuracy of the robot, which is extremely inconvenient in terms of precision control. It is.

An object of the present invention is to equalize the accuracy of the x-movement of an industrial robot having the above-mentioned triangular arm system.

That is, the robot of the present invention is composed of a control system, a drive system, and an arm system, and the control system has a control motor for z movement, preferably θ movement, housed all together in a base case, and a control motor for x movement. The drive system has a screw shaft that is operatively connected to the z-movement control motor, and supports and nuts are spaced apart above and below this screw shaft, and the drive system has a loose fit and a nut. The arm system has a triangular structure consisting of two arms connected to the nut and the support body, which are screwed together and housed in an upright case erected on the base case. Driven by an x-movement control motor, the above-mentioned triangle transforms and the robot hand moves x; driven by a Z-movement control motor, the above-mentioned triangle moves vertically in parallel; and more preferably, a θ-movement control motor. The above triangle turns and the robot hand moves by θ.

The present invention will be explained in more detail below with reference to the accompanying drawings.

FIG. 1 shows the appearance of one embodiment of the industrial robot of the present invention. Briefly, the robot is composed of three parts: a control system 1, a drive system 2, and an arm system 3. The control system 1, except for a part, is housed in a flat cylindrical base case 4 provided at the base of the robot, and the drive system 2 is housed in a long cylindrical base case 4 mounted on the base case 4. The arm system 3 consists of a plurality of arms that protrude forward from a stretchable bellows plate 7 formed on the front surface of the upright case 6, and the arm system 3 has a plurality of arms that project forward from an elastic bellows plate 7 formed on the front surface of the upright case 6. It is equipped with a robot hand H that grasps the.

FIG. 2 shows the details of the internal structure of the industrial robot having the above-mentioned schematic structure. In the figure, a part of the arm system 3 is omitted.

As described above, the drive system 2 is housed all together in the upright case 6, and has a threaded shaft 21 extending vertically, and this threaded shaft 21 is rotatably supported at the top by a bearing 21a. has been done. This screw shaft 21 has a support 22 and a nut 23.
are vertically spaced apart and loosely fitted and screwed together, respectively.

The upper support body 22 integrally has an arm support piece 22a projecting forward, and this support body also has a guide rod 1 extending vertically from the base plate 12.
5 and 15 to guide vertical movement. An arm support piece 23a is similarly formed at the front end of the nut 23. As shown in FIG. 3A, the arm system 3 has a first arm 31, a second arm 32, and a sub arm 33, and this inner sub arm 33 controls the posture of the robot hand H. Not relevant to this invention. The first arm 31 is journalled (P) at its upper end by the upper support piece 22a, extends obliquely downward, and has a robot hand H at its lower end. The second arm 32 is pivotally supported (Q) on the lower support piece 23a at its lower end, and pivotally supported (R) on the central portion of the first arm 31 in the longitudinal direction at its upper end.

The arm total 3 of the present invention has a triangular paired chain structure with the first arm 31 as the hypotenuse and the second arm 32 as the base. Therefore, when a downward load is applied to the robot hand H, the load is distributed between the first arm 31 and the second arm 32, so that extremely high rigidity can be obtained. Note that when the triangular pair chain structure is an isosceles triangle, linearity in the x-axis direction is ideal, but when functioning as a robot, it does not necessarily have to be an isosceles triangle.

In the control system 1, the x-movement control motor 11 is installed and fixed on the support piece 23a of the nut, and its output shaft is connected to the second gear via an appropriate reduction gear (not shown).
It is operatively connected to a support shaft Q at the lower end of the arm 32. This control motor 11 is a reversible motor, and as it rotates, the second arm 32 moves to the bearing point Q.
It swings up and down around the center. The other parts of the control system 1 are housed all together in the base case 4 as described above. That is, a board 12 is fitted onto the screw shaft 21, and a gear 13 is formed on the circumference of the board 12. On the other hand, a gear 16 is connected to the output shaft of the θ movement control motor 14, and this gear 16 meshes with the gear 13 on the board. Furthermore, a z-movement control motor 17 is provided below the board 12.
is provided, and its output shaft (not shown) is connected to a screw shaft 21.

Before entering into an explanation of the operation of the arm system 3, a combination of the control system 1 and drive system 2 having the above-described configuration will be explained.

When the control motor 17 rotates, the nut 23 moves vertically due to the threaded relationship between the control motor 17 and the lower nut 23. Therefore, the robot hand H moves in Z as will be described later.

When the control motor 11 rotates, the second arm 32
swings, the arm system 3 transforms as will be described later, and the robot hand H moves x.

When the control motor 14 rotates, the substrate 12, screw shaft 21, and arm system 3 rotate, and the robot hand H moves by θ.

Next, the operation mode of the arm system 3 will be explained with reference to FIGS. 3A to 3C.

First, referring to FIG. 3B, the z movement will be explained by taking as an example the case where the holder H is lowered. When the control motor 17 rotates in a predetermined direction in the state shown in FIG. 3A, the screw shaft 21 rotates and the nut 23 descends accordingly. At this time, the position of the support body 22 is determined by the raised state of the second arm 32, so there is no change in the vertical relative position of the nut and the support body, so the arm system 3 has the triangular structure shown in FIG. 3A. Descend while maintaining the In other words, it is a kind of parallel movement, so the robot hand H maintains its position in the x direction and moves from its original position h to a new position directly below it.
descends to h′.

Similarly, when the control motor 17 rotates in the opposite direction, the robot hand H maintains its position in the x direction and rises from its original position h to a new position directly above it.

Next, x movement will be explained with reference to FIG. 3C, taking as an example the case where the robot hand H moves forward. When the control motor 11 rotates in a predetermined direction in the state shown in FIG. 3A, the second arm 32 swings downward about the bearing point Q and pulls the bearing point R downward. Accordingly, as the upper support body 22 loosely fitted onto the screw shaft 21 approaches the lower nut 23, the triangular structure shown in FIG. 3A collapses and becomes a triangular structure that is flatter than before. In other words, the robot hand H maintains its z-direction position and moves from its original position h to a new outer position.
Move forward to h″.

Similarly, when the control motor 11 rotates in the opposite direction, the robot hand H maintains its z-direction position and retreats from its original position h to a new inner position.

In the above, x movement and z movement have been separated for the convenience of explanation, but in practice, it is also possible to perform two-dimensional movement in xz by overlapping the rotations of both control motors, and furthermore, it is possible to perform two-dimensional movement in xz by overlapping the rotations of both control motors. It is also possible to perform three-dimensional movement in xzθ by overlapping the rotations of the motor 17.

Commercially available reversible motors are suitably used as these control motors, and are excited in relative relation to each other by electrical signals generated according to suitably set programs.

As is clear from the above, in this invention,
The arm system adopts a triangular structure consisting of two arms, and the control system is housed in the base case except for a part, so it not only has all the performances of the robot proposed above, but also Since the x-movement control motor is directly connected to the arm system, the accuracy of x-movement operation is greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the external appearance of one embodiment of the industrial robot of the present invention, Fig. 2 is a partially omitted perspective view showing its internal structure, and Figs. 3 A to C are side explanatory views showing its operation. It is. 1...Control system, 2...Drive system, 3...Arm system, H...
Robot hand, 14...θ movement control motor,
11...x movement motor, 17...z movement control motor, 21...screw shaft, 22, 23...nut, 3
1, 32...Arm.

Claims (1)

[Claims] 1. A screw shaft 21 extending in the vertical direction is operatively connected to the Z movement control motor 17 at its lower end or upper end, and a support 22 and a nut 23 are vertically spaced apart from each other on the screw shaft. The support body is supported by the guide rod 15 so as to be slidable in the vertical direction, and the first arm 31 is pivotally supported on the support body at the upper end, and the second arm 32 is supported by the support body at the upper end. The lower end of the second arm 8 is rotatably supported on a nut, and the upper end of the second arm 8 is rotatably supported on the central portion of the first arm in the longitudinal direction, so that the arm system has a triangular paired chain structure. is constructed and fixed, and the output shaft of the control motor is operatively connected to the lower end of the second arm, so that the second arm is oscillated and the triangular shape of the arm system is transformed. An industrial robot. 2 Substrate 12 that supports a drive system such as screw shaft 21
The industrial robot according to claim 1, wherein the robot is operatively connected to the θ movement control motor 14.