JPS59167486A - Spring balancing mechanism for horizontal arm - 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 a spring balance mechanism for balancing the rotational moment due to gravity of a horizontal arm used in an articulated painting robot, an articulated welding robot, etc.

FIG. 1 shows a side view of a conventional general painting robot, and FIG. 2 shows a schematic internal mechanism thereof.

That is, as shown in FIG. 1, such a painting robot has a swivel base 20 that can freely rotate in a horizontal plane about a vertical axis 1, and a rotating base 20 that swings in a vertical plane that includes the vertical axis 1. A horizontal arm 4 that can swing in a vertical plane including the vertical axis 1 is attached to one end of this vertical arm 3, and a painting gun, etc. is attached to the tip of this horizontal arm 4. By setting up the wrist 5 for attaching the swivel base 2 and the swinging freedom of the vertical arm 3 and horizontal arm 4, the wrist 5 can be moved to any desired position and painting work can be done. This is what we do.

In the above-mentioned painting robot 1-, the work OL trace on the wrist 5 follows an extremely complicated path, so generally when teaching, the operator directly touches the wrist 5, but when performing such direct teaching, In order to do this, it is necessary to release the locked state so that the horizontal arm 4 and vertical arm 3 can swing freely. Therefore, the gravity of the horizontal arm 4, etc. must be balanced in some way. The entire gravity of these arms is applied to the operator, making teaching work extremely tiring.

Therefore, in conventional painting robots, etc., as shown in Figure 2,
A triangular plate 6 is attached to the end of the horizontal arm 4, and a balance spring 9 is attached between the fulcrum 7 at the top of the triangular plate 6 and the fourth intermediate fulcrum 8 of the horizontal boot J, and the swinging fulcrum of the horizontal arm 4 is A rotational moment consisting of the product of the distance (moment arm) rl from IO to the balance spring 9 and the tension Fl of the balance spring 9 is applied to the horizontal arm 4, and the horizontal arm 4
Both moments are balanced by counteracting the rotational moment due to its own weight.

The gravitational moment of the vertical arm 3 is determined by the fulcrum 12 fixed directly above the swing fulcrum 11 of the vertical arm 3 provided on the swivel base 2.
and the swinging fulcrum 1o of the horizontal arm 4.
3 and the distance between the fulcrum 12 and the vertical arm 3! 1i
lt (moment arm) The rotational moment formed by the product of r2 and the tension F of the balance spring 13 is transferred to the vertical arm 3.
It is balanced by each feeding.

In the figure, 14 is a hydraulic cylinder for driving the vertical arm 3;
This is an actuator made of a ball screw or the like. Also 15
1. is an actuator for driving the horizontal arm 4, and is installed between the midpoint of the horizontal arm 4 and the fulcrum of the swivel base 2. The horizontal arm 4 is driven to swing around the swing fulcrum 10 by this actuator (drive source).

If a balance mechanism such as such a balance spring 9 is used, it is possible to eliminate the gravitational moment of the horizontal arm 4), but in such a mechanism, the balance spring 9 is connected to the fulcrums 7 and 8 as shown in FIG. Since the balance spring 9 is attached between the horizontal arm 4 and the horizontal arm 4, a drive system is installed to drive the horizontal arm 4-digit IQ-5. Prevent interference with Harance spring 9 1
Because of this, the structure of the drive system becomes complicated and the horizontal arm becomes large.

Therefore, an object of the present invention is to provide a spring mechanism for balancing the gravitational moment of the horizontal arm on a swivel table separate from the horizontal arm, thereby solving the drawbacks inherent in the conventional balance mechanism as described above. A horizontal arm that is attached to the tip of a vertical arm that swings in a vertical plane, swings in the vertical plane, and is driven to swing by a drive source installed between it and the swivel base. A device for balancing rotational moment due to gravity, comprising: 1- a horizontal shaft fixed to the horizontal arm; - the vertical arm;
A parallel link mechanism is formed by a link arm parallel to the horizontal axis and a link arm parallel to the vertical arm. The present invention provides a spring balance mechanism for a horizontal arm, the gist of which is a connection of balance springs that are biased in the direction of swinging against its own weight.

Next, embodiments embodying the present invention will be described with reference to FIGS. 3 and 4 to provide an understanding of the present invention. here the third
The figure is a schematic configuration diagram showing the entire structure of a horizontal arm spring balance mechanism according to an embodiment of the present invention, and FIG. 4 is a perspective view of a spring mechanism part that can be used in the same embodiment.

In FIG. 3, 20 is a swivel base with a vertical shaft 21 as described above.
It is possible to turn in a horizontal plane around , and this turning table 2
A support shaft 22 whose position is fixed on the swivel base 20 is attached to a vertical shaft 210, which is the center of rotation of the robot. It is attached so that it can swing. vertical arm 23
A horizontal arm 25 that can swing in the vertical plane is attached to a fulcrum 24 at the tip of the horizontal arm 25, and a horizontal arm 25 is attached to a fulcrum 24 at the tip of the The support shaft 22 for swinging the arm 25 has a T that is perpendicular to the horizontal shaft 22 and rotatable around the support shaft 22.
A letter-shaped link arm 28 is attached.

On the other hand, the horizontal arm 25 is attached to its distal end (or the horizontal arm 25
The horizontal shaft 29 (forming part of the link arm 28 itself) has an integral horizontal shaft 29, and the length of this horizontal shaft 29 is the length between the supporting point 31 provided on the body 30 of the link arm 28 and the supporting shaft 22. is set equal to the distance of

The fulcrum 31 provided on the body 30 of the link arm 28 and the fulcrum 32 provided at the tip of the horizontal shaft 29 are at a distance equal to the distance between the supporting shaft 22 and the fulcrum 24 of the vertical arm 23. They are connected by a third link block F' 33.

Therefore, the vertical arm 23, the link rod 33 parallel to the vertical arm 23, the horizontal shaft 29, and the body 30 of the link arm 28 parallel to the horizontal shaft 29 constitute a parallel link mechanism 35.

Furthermore, a first balance spring 3 is attached to the wing portion 36a of the link arm 28, one end of which is attached to a fulcrum 38 whose position is fixed to the swivel base 20, and which is disposed behind the vertical arm 23.
The other end of 9 is attached to the moon.

The other wing portion 361 of the link arm 28. fulcrum 3
A second balance spring 41 disposed in front of the vertical arm 23 is attached between the pivot point 7b and the fulcrum 40 whose position is fixed to the swivel base 20.

The above-mentioned balance springs 39 and 41 are both tension springs that urge the link arm 28 to rotate in the clockwise direction shown in FIG. 3 around the support shaft 22.

Therefore, when the first and second balance springs 39 and 41 bias the link arm 28 clockwise in FIG.
Since the body 30 of the arm 28 rotates in the horizontal direction, when the vertical arm 23 is fixed, the horizontal shaft 28, which is flat 0, is urged to rotate clockwise about the fulcrum 24. , the horizontal arm 25 having the horizontal shaft 29 integrally is also urged in the horizontal direction around the fulcrum 24, and the horizontal arm 25 is rotated by its own weight (in the counterclockwise direction).
The horizontal arm 25 is urged to rotate in a direction opposite to the force direction), and the rotational moment of the horizontal arm 25 due to gravity is balanced.

1- Balance springs 39 and 41 as described above are provided one each on the left and right sides with the vertical arm 23 in between, as shown in FIG. 4, to balance the rotational moment caused by the balance springs about the vertical arm 23.

Incidentally, in order to adjust the rotational force generated by the first and second balance springs 39 and 41, the spring portion and the rond portion are connected by an adjustment nut 42.

In the case of the balance mechanism shown in FIG. 3, the rotational moment for urging the horizontal arm 25 to rotate against gravity is the urging force of the first and second balance springs, the fulcrum 38.40 The position of horizontal arm 2
The rotational moment due to gravity of the horizontal arm (hereinafter referred to as gravitational moment), which changes according to the swing angle of 5, is approximately matched with the rotational moment due to the balance spring (hereinafter not referred to as balance moment), and the horizontal arm 25 can be shaken lightly to make a rattling sound.

As described below, the present invention is attached to the tip of a vertical arm that swings in a vertical plane, swings in the vertical plane, and is mounted between a rotating base and a drive → DI source. Rocking-
A device for balancing the rotational moment due to gravity of a horizontal arm that is moved, which includes a horizontal axis fixed to the horizontal arm, the vertical arm, a link arm parallel to the horizontal axis, and a link parallel to the vertical arm. A parallel link mechanism is formed by the rod, and further 1- to the nkua-m,
1-This is a spring balance mechanism for a horizontal arm, which is characterized by connecting balance springs that are arranged on the front, rear, left and right sides of the article surface arm, and that bias the horizontal arm in a direction to swing against its own weight. , there is no need to provide any balance mechanism in the horizontal arm, the weight of the horizontal arm can be reduced, and its structure can be simplified;
Since the balance spring can be provided at the base of the vertical arm where it does not interfere with the rotation transmission mechanism in the horizontal arm, the degree of freedom in designing the rotation transmission mechanism is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional welding robot, etc., FIG. 2 is a schematic configuration diagram showing the gravity balance mechanism of the same robot, and FIG. 3 is a configuration diagram showing a spring balance mechanism which is an embodiment of the present invention. FIG. 4 is a perspective view, not showing parts, of a spring mechanism that can be used in this embodiment. (Explanation of symbols) 23...Vertical arm, 25...Horizontal arm 2
9...Horizontal axis, 28...Link arm 3
3...Link rod 39.41...First and second balance springs 35...
Parallel link mechanism. Applicant Tralfani/Niss Agent Patent Attorney Takeo Honjo Figure 3 29 Figure 4

Claims (1)

[Claims] 1. Rotation moment due to gravity of a horizontal arm that is attached to the tip of a vertical arm that swings in a vertical plane, swings in the vertical plane, and is driven to swing by a drive source installed between it and the swivel base. A device for balancing, wherein a parallel link mechanism is formed by a horizontal axis fixed to the horizontal arm, the vertical arm, a link arm parallel to the horizontal axis, and a link arm parallel to the vertical arm, Furthermore, for a horizontal arm, the link arm is connected to balance springs that are arranged on the front, rear, left and right sides of the vertical arm and bias the horizontal arm in a direction to swing against its own weight. Honey balance mechanism.