JPH0424200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a horizontal articulated industrial robot used for various industrial applications.

Conventional Structure and Its Problems As shown in FIGS. 1 and 2, the horizontal articulated industrial robot has a rotary actuator 3 connected to a fixed base 1 via a first rotary shaft 2. A first arm 4 whose one end is rotatably supported is pivotally mounted, and a rotary actuator 6 parallel to the first rotation axis 2 is attached to the other end of the first arm 4.
A second arm 7, which is also rotatably supported at one end, is pivotally connected via a second rotating shaft 5 having a second rotary shaft 5, and is connected to the tip of the second arm 7 to an actuator 9 for vertical movement. A tool holder 10 is pivotally mounted via a third rotation axis 8 parallel to the second rotation axis 5 and is slidably and rotatably supported.

As a means for controlling the rotational posture of the tool holder 10 about the third rotation axis 8, the toothed belt teeth 11 connected to the rotation actuator 17 are connected to the first rotation axis 2, and the second rotation axis 5 A toothed belt wheel 12 integrally supported in two stages and rotatably supported.
and 14, and the third rotating shaft 8, the tool holding part 1
A toothed belt wheel 15 rotatably supported integrally with the toothed belt wheel 15 is disposed, and between each toothed belt wheel,
This is accomplished by driving the rotary actuator 17 by connecting the toothed belts 13 and 16 stretched together. Further, in the above configuration, the toothed belt wheels 11, 12, 14 and 15 have the same pitch diameter. The reason for this is that by making the pitch diameter the same, no matter what position the first arm 4 and second arm 7 move to, without having to turn the rotary actuator, they will be able to move according to the amount of rotational movement. This is because a corrective rotational movement is automatically applied to the third rotation axis, and the rotational posture of the tool holder 10 is always kept constant. (Such a parallel movement configuration is generally employed in drafting instruments and the like).

With the above configuration, the robot becomes a horizontally articulated robot with four degrees of freedom, and by controlling each actuator, it can move arbitrarily within a range of motion on a plane. However, in the field where robots are used in general, depending on the application, there is an extremely strong need for robots that have at least a degree of freedom and are less expensive. For this reason, there are many horizontal articulated robots that only move the tool holding shaft 10 up and down by using a pneumatic cylinder or the like (no movement distance control) that simply drives the vertical movement actuator 9 back and forth.

This is because although the degree of freedom is three, it is possible to significantly reduce costs in terms of control and the like. FIG. 3 shows a conventional example.

7 is a second arm, 9 is a pneumatic cylinder, 10 is a tool holder, and 21 is a holder that is rotatably supported by the second arm 9 and serves as a sliding guide in the axial direction while regulating the rotation of the tool holder 10. , 15 is a toothed belt wheel which is fixed to the holder 21 and which gives a rotational attitude to the tool holder by means of a toothed belt 16. In the above configuration, the driving force of the pneumatic cylinder fixed to the second arm 7 causes the tool holder 10 to slide up and down via the connecting fitting 19, and its movable stroke is controlled by the bolts attached to the connecting fitting 19. 18 is determined by the moving distance P until it comes into contact with the stopper pin 20, and is constant. (The moving distance P is
It can be adjusted with the bolt 18, but once set it remains constant. ) For this reason, as shown in Fig. 2, for example, when transferring an article from position A to position B during handling work, etc., the supply height of the article at position A,
This method has the disadvantage that the heights of the transfer and loading positions at position B must always be the same height, which significantly narrows the scope of application in terms of robot usage.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention aims to improve the supply height and transfer of articles even when the vertical sliding actuator of an industrial robot is an actuator that reciprocates at a constant stroke between two predetermined points, such as a pneumatic cylinder. To provide an inexpensive industrial robot that can vary and adjust the vertical sliding stroke of a tool holder at each point, even if the heights are not necessarily the same.

Composition of the Invention The present invention is directed to a so-called horizontally articulated industrial robot having a plurality of parallel rotation axes, in which a tool holder at the tip is driven by an actuator such as a pneumatic cylinder whose position in the vertical direction cannot be controlled. , the vertical position control of the tool holding section is as follows:
Using the relative positional relationship between the tool holder and the actuator, the above-mentioned position corresponding to the position of the tool holder in the horizontal plane is used via a holder that rotates and moves by a posture holding function that moves in parallel with the rotation of each arm. Regulating the vertical drive position of the actuator 1
This is accomplished by providing one or more stoppers, and has the advantage of being able to perform handling operations between a plurality of different vertical positions with an inexpensive structure.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a front sectional view of the third rotating shaft portion of the horizontal articulated robot in the embodiment of the present invention, and FIG.
The figure is a cross-sectional view taken along the line Q--Q in FIG. 4. The configuration of the main body of the horizontal articulated industrial robot and the attitude control means centered on the third rotation axis of the tool holder are the same as those shown in FIGS. 1 and 2 and have already been explained above. is omitted. Accordingly, the third rotating shaft portion, which is the key point of the present invention, will be explained with reference to FIGS. 4 and 5. 22 is the second arm of the horizontal articulated robot; 23 is a pneumatic cylinder 24 for reciprocating between two points fixed to the second arm 22; one end is fixed to the movable part of the pneumatic cylinder; the other end is fixed to the second arm 22; A connecting fitting is connected to the tool holding part 27 via the rotation bearing 26, and 28 is a second connecting fitting.
Rotatably supported by the arm 22, the tool holder 2
7 as a sliding guide in the axial direction while regulating rotation through a key 30, and has a V-shaped groove 29 on its flange that is concentric with the center of rotation and narrows the opening outward. . 31 and 32 are stoppers each having a predetermined length;
It is fixed in a predetermined position at an angle a through a V-shaped nut 33 that is fitted into the V-shaped nut 33. A toothed belt wheel 35 is fixed to the holder 28 and provides a rotational attitude to the tool holder 27 by means of a toothed belt 36.

The operation of the third rotating shaft portion configured as described above will be described below.

First, when performing handling work etc. with an industrial robot, consider the case where an article is supplied at point A and transferred to point B, as shown in Figure 2.The operation of the third rotating shaft at point A is as follows. , the tool holder 27 is lowered by the pneumatic cylinder 23 via the connecting fitting 24, and the bolt 25 comes into contact with the stopper 31, that is, the bolt 25 descends by _one stroke, and is actually attached to the tip of the tool holder 27. The article can be gripped by a gripping device or the like. When you grasp an item,
The tool holder 27 rises, each arm of the robot then rotates, and the third rotation axis moves to a predetermined point B. At this time, even if the rotational actuator 17 does not operate, each arm rotates, and the third rotation axis is set at an angle corresponding to the amount of rotational movement of each arm by the attitude control means. Rotated by a. That is, the tool holding part 27 is rotated by the angle a together with the holder 28.

Therefore, at point B, when the tool holder 27 is lowered again by the pneumatic cylinder 23, the bolt 25 attached to the connecting fitting 24 moves from the stopper 31 at an angle a about the third rotation axis. Stopper 32 set in a remote position
, the downward stroke can be changed to P ₂ .

In this way, from the starting point of the third rotation axis of the robot arm with respect to the center position of the first rotation axis,
If the movement angle of the points to be moved sequentially is known in advance, stoppers 31 and 32 of different lengths, etc., are set on the flange surface of the holder 28 in order according to the predetermined movement angle. , the downward stroke of the tool holder 27 can be successively changed. In this embodiment, the stoppers 31 and 32 are connected to the holder 28.
A V-shaped groove 29 is provided on the circumference of the flange portion of the flange, and the V-shaped groove 29 is concentric with the center of rotation and has a narrow opening on the outside. Although the V-shaped groove can be fixed at any position on the circumference, the V-shaped groove may be replaced with a T-shaped groove, and instead of a groove, a plurality of tapped holes can be provided. The stoppers 31 and 32 may be attached by selecting the following.

Further, in this embodiment, as a means for controlling the rotational posture of the tool holder 27 about the third rotation axis,
The parallel movement means is a toothed belt wheel with the same pitch size and diameter arranged at the rotation axis of each arm, but it can also be used as a link mechanism that forms a parallelogram that swings around the rotation axis of each arm. Similar effects can be found.

Effects of the Invention As described above, the present invention provides an inexpensive reciprocating actuator (pneumatic cylinder, etc.) for the sliding of the tool holder at the tip in a horizontal articulated robot having a plurality of parallel rotation axes. A stopper that changes the relative positional relationship with the actuator in the horizontal plane is used to control the position of the dynamic stroke by utilizing the rotation index of the tool holder obtained by the posture control function using the rotation axis of each robot arm. By providing a means to do this, it is possible to significantly reduce costs in terms of control, etc., and the scope of application of robots can be expanded, and the effects are significant. .

[Brief explanation of drawings]

Figure 1 is a front view of the horizontally articulated robot, Figure 2
The figures are a top view of Fig. 1, Fig. 3 is a front sectional view of the third rotating shaft part in the conventional example, Fig. 4 is a front sectional view of the third rotating shaft part in the present embodiment, and Fig. 5 is a front sectional view of the third rotating shaft part in the conventional example. It is an arrow view of the QQ cross section in the figure. 1... Base, 2... First rotating shaft, 3... First
Arm rotation drive means (rotary actuator),
4...First arm, 5...Second rotating shaft, 6...Rotation drive means (rotary actuator) for the second arm,
7...Second arm, 8...Third rotation axis, 27,1
0...Tool holding part, 23...2 in the direction of the third rotation axis
Actuator (pneumatic cylinder) that reciprocates between points, 25... Contact portion (bolt), 31, 32...
...Stopper, 11...First toothed belt wheel, 12
...Second toothed belt pulley, 14...Third toothed belt pulley, 15, 35...Fourth toothed belt pulley, 1
3,16...Toothed belt.

Claims (1)

[Scope of Claims] 1. A first arm whose one end is rotatably supported by a base via a first rotating shaft, a driving means for rotationally driving this arm, and the other end of the first arm. a second arm rotatably supported via a second rotation axis parallel to the first rotation axis; a driving means for rotationally driving the second arm; and a distal end of the second arm; a tool holding part rotatably supported via a third rotation axis parallel to the second rotation axis and slidable in the direction of the third rotation axis; an actuator that reciprocates the holding part with respect to the second arm between two points in the third rotation axis direction; and the tool holding part;
attitude control means for keeping a rotational attitude about the third rotational axis constant regardless of rotation of the first and second arms;
Rotates integrally with the tool holder and has an immovable relationship with the second arm in the direction of the third rotation axis, and moves the tool holder in one direction in the third rotation axis direction. tool holder positioning means for preventing the tool holder from moving; An industrial robot having the same circumference centered on the third rotating shaft and having a radius equal to the distance between the third rotating shaft and the contact portion of the actuator. 2 The stopper of the tool holder positioning means is
The industrial robot according to claim 1, wherein the directional position of the third rotating shaft can be adjusted. 3 The stopper of the tool holder positioning means is
The industrial robot according to claim 1, wherein the industrial robot is movable on the same circumference with respect to the tool holding portion positioning means. 4 The above-mentioned attitude control means includes first and second rotary shafts rotatably provided on the first rotation shaft and the second rotation shaft, respectively.
a toothed belt wheel, a toothed belt stretched between the two toothed belt wheels, and a third toothed belt wheel that is coaxial and has the same diameter as the second toothed belt wheel and rotates integrally with the second toothed belt wheel. a fourth toothed belt wheel that rotates around a third rotation axis and rotates integrally with the tool holding part;
The industrial robot according to claim 1, comprising a toothed belt stretched between said third and fourth toothed belt wheels, and wherein said first toothed belt wheel is fixed to a base.