JPH0615156B2 - Industrial robots - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an industrial robot, and more particularly, to a balance device that is of a vertical articulated type and reduces a load torque increase due to an arm's own weight and a load torque variation due to a posture change. The present invention relates to an equipped industrial robot.

[Common technology]

In general, an industrial robot, particularly a vertical multi-joint type, has a first arm that swings in a vertical plane with a rotary shaft installed on a swivel base as a first joint, and is provided at the tip of the first arm. It is composed of a second arm that swings in a vertical plane with the rotating shaft as a second joint, and a wrist portion that changes the posture of the end effector attached to the tip.

In a vertical articulated robot in which the arm swings in a vertical plane in this way, unlike a horizontal articulated robot such as a SCARA type, the arm is affected by gravity, and therefore the load torque increases and the load torque increases due to the weight of the arm. The load torque fluctuates due to the posture change.

For this reason, there may be a problem that the drive source of the arm, for example, the electric motor becomes large or the drive control is not easy, and there is a device provided with a balance device for reducing increase and fluctuation of the load torque.

[Conventional technology]

As an industrial robot equipped with a conventional balancing device,
For example, the coating robot 855 manufactured by Tokiko Co., Ltd. and the industrial robot RV-242 manufactured by Mitsubishi Electric Co., Ltd., which are included in the Industrial Robot Catalog Guide for 1983 issued by the Japan Industrial Robot Manufacturers Association. There is.

FIG. 3 is a front view showing an example of an industrial robot structure provided with a conventional balancing device, and FIG. 4 is a side view. In the figure, an arm 5 is axially supported by a concave joint base 2 installed on a swivel base 1, and can be swung in the direction of an arrow by a servo motor 6 and a speed reducer 7. Also, arm 5
Between the joint base 2 and the joint base 2, two balance devices 8 are attached to both side surfaces of the arm 5 to prevent the arm 5 from rotating due to its own weight in a posture in which the arm 5 swings as shown by a broken line. Has been. The balance device 8 includes a cylindrical cylinder 9'and a piston 1 sliding inside the cylinder 9 '.
0, a rod 12 which is connected to the rod 0 and penetrates the bottom 11 of the cylinder, and a coil spring 13 which is compressed and held between the piston 10 and the bottom 11 of the cylinder. Here, the upper end 21 of the cylinder 9'is pivotally supported by a pin 15 'which is planted outside the side surface of the arm 5, while the lower end 16 of the rod 12 is opposite the upper end 17 on both sides of the concave joint base 2. It is pivotally supported by a pin 22 implanted in the. When the arm 5 swings as shown by the broken line, the distance between the pin 15 'and the pin 22 becomes long, so that the coil spring 13 is compressed and a rotational torque is generated in the method of lifting the arm 5.

[Problems to be solved by the invention]

The industrial robot equipped with the above-described conventional balancing device has a drawback that the wiring and piping arranged along the arm for the end effector may be caught and broken because the balancing device is exposed and attached to the outside of the arm. there were. In addition, since the balance device is arranged in two pieces, one on each side surface of the arm so that the forces applied to the joint base and the arm are evenly distributed to the left and right, the number of parts is large and the cost is high. Furthermore, it not only takes time to clean the outer surface of the robot, but also significantly hinders the improvement of the external design of the robot.

[Means for solving problems]

The industrial robot of the present invention connects a concave joint base installed on a swivel base, an arm pivotally supported by the joint base, and an upper end on both sides of the concave joint base. Shaft, the arc-shaped long hole formed in the arm by the swing angle so as not to interfere with the shaft when the arm swings, and the opening edge is pivotally supported by the pin implanted on the inner surface of the arm. A cylindrical cup-shaped cylinder placed inside,
A piston that slides in the cylinder, a rod that has one end connected to this piston and the other end that penetrates the bottom of the cylinder and is axially supported by the center of the shaft, and a coil spring that is compressed and held between the bottom of the cylinder and the piston. It is configured to include and.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a front sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional side view of the industrial robot shown in FIG.

In the figure, bearings 3 are mounted on both sides of a concave joint base 2 installed on a swivel base 1, and a rotary shaft 4 is pivotally supported. An arm 5 is attached to the rotary shaft 4 and can be swung in the direction of the arrow by the servo motor 6 and the speed reducer 7. The arm 5 has a built-in balance device 8 that prevents the arm 5 from rotating under its own weight when the arm 5 swings as shown by the broken line. This balance device 8
Is a cylindrical cup-shaped cylinder 9, a piston 10 swinging inside the cylinder 9, a rod 12 connected to the cylinder 10 and penetrating a bottom portion 11 of the cylinder, and compressed between the piston 10 and the bottom portion 11 of the cylinder. Held coil spring 13
It is composed by. Here, the opening edge portion 14 of the cylinder 9 in the shape of a cylindrical cup is the pin 1 planted on the inner surface of the arm 5.
5 is pivotally supported and, on the contrary, the lower end 16 of the rod 12
Is pivotally supported at the center of a shaft 18 that connects upper end portions 17 on both sides of the concave joint base 3. Open edge 14 pin 1
The reason why the balance device 8 is axially stopped is to shorten the entire length of the balance device 8 and facilitate the incorporation of the arm 5. The arm 5 has an arc-shaped elongated hole 19 corresponding to the swing angle so as not to interfere with the shaft 18 when the arm 5 swings as shown by a broken line.
Has been opened. In order to prevent the strength of the arm 5 from decreasing due to the elongated hole 19, the arm member 20 in the portion where the elongated hole 19 is formed is made thicker than the arm members 20 'in the other portions. When the arm 5 swings as shown by a broken line, the distance between the pin 15 and the shaft 18 becomes long, so that the coil spring 13 is compressed and a rotational torque is generated in a direction to lift the arm 5. Therefore, an increase in load torque due to the weight of the arm can be reduced.

〔The invention's effect〕

In the industrial robot of the present invention, the balance device, which has been conventionally exposed one by one on the outside of each side surface of the arm, is incorporated in the arm, so that wiring and piping arranged along the arm for the end effector can be provided. There is an advantage that there is no fear of getting caught. Further, since only one balancing device is arranged on the center line of the robot, there is an effect that the number of parts is reduced and the cost is reduced. Furthermore, not only the outer surface of the robot can be easily cleaned, but also the appearance design of the robot can be significantly improved.

[Brief description of drawings]

1 is a front sectional view showing an embodiment of the present invention, FIG. 2 is a side sectional view of the industrial robot shown in FIG. 1, FIG. 3 is a front view showing an example of the conventional art, and FIG. It is a side view of the industrial robot shown in FIG. 1 ... Swivel base, 2 ... Joint base, 3 ... Bearing, 4 ...
… Rotation axis, 5 …… arm, 6 …… servo motor, 7 ……
Reduction gear, 8 ... Balance device, 9, 9 '... Cylinder,
10 ... Piston, 11 ... Bottom of cylinder, 12 ...
Rod, 13 ... Coil spring, 14 ... Opening edge, 15
...... Pin, 16 …… Lower end of rod, 17 …… Upper end of joint base, 18 …… Shaft, 19 …… Oval hole, 20, 2
0 '... arm member, 21 ... upper end of cylinder, 22 ...
…pin.

Claims (1)

[Claims] 1. A shaft for connecting a concave joint base mounted on a swivel base, an arm pivotally supported by the joint base and swinging, and upper ends of both sides of the concave joint base. The opening edge is pivotally supported by an arc-shaped elongated hole formed in the arm by an amount corresponding to the swing angle so as not to interfere with the shaft when the arm swings, and a pin implanted on the inner surface of the arm. A cylindrical cup-shaped cylinder disposed inside the arm, a piston that slides in the cylinder, one end connected to the piston and the other end penetrating the bottom of the cylinder, and axially supported at the center of the shaft. Industrial robot comprising: a compressed rod and a coil spring compressed and held between the bottom of the cylinder and the piston.