JPH0970789A - Balancing device of articulated robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent moment balance of a horizontal arm without increasing the inertia or limiting the operational range of a robot. SOLUTION: When a horizontal arm drive shaft 12 in a casing 16 is turned, the force is transmitted to a horizontal arm through a horizontal arm drive link to oscillate the horizontal arm. The horizontal arm is provided in an oscillating manner on the top part of a vertical arm 2. An adjustment flange 22 of a balancing device 20 is provided on the casing 16 with the circumferential fitting position in the variable condition. A torsion coil spring 21 is inserted between the casing 16 and the horizontal arm drive shaft 12 to give the torque to balance the horizontal arm to the shaft 12. The angle of torsion of the spring 21 is adjusted by changing the circumferential position of the flange 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device for an articulated robot, which is devised so that a horizontal arm can be well balanced without increasing inertia.

[0002]

2. Description of the Related Art An example of a conventional articulated robot will be described with reference to FIG. As shown in the figure, the main body pedestal 01 is provided with a vertical arm 02 which is swingable via a bearing (not shown). A horizontal arm 05 is swingably provided on the top of the vertical arm 02 via a horizontal arm support shaft 04. Tip of horizontal arm 05 (right end in the figure)
Then, the work is gripped via a work clamp hand or the like (not shown). Rear end of horizontal arm 05 (left end in the figure)
A horizontal arm link 09 is attached via a horizontal arm link shaft 08, and a left end of a horizontal arm drive lever 011 is attached to a lower end of the horizontal arm link 09 via a horizontal arm link lever shaft 010. The right end of the horizontal arm drive lever 011 is fixed to a horizontal arm drive shaft (not shown).

In the articulated robot having the above structure, the moment about the horizontal arm support shaft 04 is likely to be always applied to the side on which the work is suspended, that is, the clockwise moment in FIG. To counter this, conventionally, a weight 013 is provided on the side opposite to the work with respect to the horizontal arm support shaft 04, and a tension spring 014 for assisting the return of the vertical arm 02 is provided.

Further, in a robot which requires a drive function for the tip hand, the hand drive function is provided at the rear end (left end) of the horizontal arm 05. In addition, a tension spring for assisting the return of the horizontal arm 05 may be provided.

[0005]

By the way, the horizontal arm 0
When the weight 013 is provided in order to balance the moment of 5, the inertia increases by the weight 013, which impedes high-speed motion. Furthermore, since the space in which the weight 013 moves easily interferes with the movement range of other arms, the movement range of the robot is restricted.

On the other hand, a robot that does not require the drive function of the tip hand cannot equip the hand drive function to balance the moments. Also horizontal arm 0
Attaching a tension spring to 5 was difficult.

Further, in the prior art, the weight of the weight 013 and the spring force of the tension spring 014 cannot be changed. Therefore, the torque applied to balance the moment could not be changed during the continuous operation in response to the change in the work weight.

In view of the above-mentioned conventional technique, the present invention is capable of changing / adjusting the torque to be added for moment balance without increasing the inertia, and without restricting the range of motion of the robot. It is an object of the present invention to provide a compact balance device for an articulated robot.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a horizontal arm drive shaft provided in a casing,
A vertical arm swingably provided with respect to the casing, a horizontal arm swingably provided at the top of the vertical arm and having a work piece at a tip end side thereof, and a driving force of the horizontal arm drive shaft A balance device for a multi-joint robot having a horizontal arm drive link for transmitting to the rear end side of the horizontal arm to swing the horizontal arm, the balance device being provided in the casing and occurring at the front end side of the horizontal arm. It is characterized in that it is connected to the horizontal arm drive shaft so as to give a torque to the horizontal arm drive shaft which causes a moment opposite to the moment.

Further, according to the present invention, a horizontal arm drive shaft provided in a casing, a vertical arm swingably provided with respect to the casing, and a swingably provided on a top portion of the vertical arm. A balance device provided for a multi-joint robot having a horizontal arm having a work piece at its tip side and a horizontal arm drive link for transmitting the driving force of the horizontal arm drive shaft to the rear end side of the horizontal arm to swing the horizontal arm. And a torsion coil spring whose one end is connected to the horizontal arm drive shaft so as to impart a torque to the horizontal arm drive shaft, which produces a torque that is opposite to the moment generated on the distal end side of the horizontal arm. , The other end of this torsion coil spring is connected, and the mounting position can be adjusted along the rotation direction for adjusting the torsion angle of the torsion coil spring. And adjustment flange attached to the casing, to become in the features.

Further, according to the present invention, a horizontal arm drive shaft provided in a casing, a vertical arm swingably provided with respect to the casing, and a swingably provided on a top portion of the vertical arm. A balance device provided for a multi-joint robot having a horizontal arm having a work piece at its tip side and a horizontal arm drive link for transmitting the driving force of the horizontal arm drive shaft to the rear end side of the horizontal arm to swing the horizontal arm. The rotating shaft for output, which is provided in the casing, applies torque to the horizontal arm drive shaft to generate a torque that is opposite to the moment generated on the tip side of the horizontal arm. It is characterized in that it is provided with a rotary actuator which is connected to the horizontal arm drive shaft and whose output torque changes according to the pressure of the supplied fluid.

In the present invention, the balance device imparts torque to the horizontal arm drive torque to balance the moments acting on the horizontal arm. Since the balancer is provided in the casing of the horizontal arm drive shaft, it does not increase the inertia and does not limit the range of motion of the robot. Further, by adjusting the position of the adjusting flange, the torsion angle of the torsion coil spring can be adjusted, and the fluid pressure supplied to the rotary actuator can be adjusted to adjust the torque applied for moment balance.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIG. 1 showing the whole multi-joint robot, FIG. 2 which is an AA cross section of FIG. 1 and FIG. 3 which is a BB cross section of FIG. .

As shown in FIG. 1, the main frame 1 is provided with a vertical arm 2 which is swingable via a vertical arm support bearing 3 (see FIG. 2). A horizontal arm 5 is swingably mounted on the top of the vertical arm 2 via a horizontal arm support shaft 4. At the tip of the horizontal arm 5 (the right end in the figure), the work is gripped or sucked via the work clamp hand 6. A horizontal arm link 9 is attached to the rear end (left end in the figure) of the horizontal arm 5 via a horizontal arm link shaft 8, and a lower end of the horizontal arm link 9 is driven by a horizontal arm link lever shaft 10 to drive the horizontal arm. The left end of the lever 11 is attached. The right end of the horizontal arm drive lever 11 is fixed to the horizontal arm drive shaft 12. The horizontal arm drive shaft 12 is provided in the casing 16.

When the horizontal arm drive shaft (12) is rotated by the horizontal arm drive source (motor), this force is applied to the horizontal arm drive shaft 12 → horizontal arm drive lever 11 → horizontal arm link lever shaft 10 → horizontal arm link 9 → It is transmitted to the horizontal arm 5 via a path (horizontal arm drive link) called the horizontal arm link shaft 8. As a result, according to the rotation of the drive shaft 12, the horizontal arm 5 swings around the horizontal arm support shaft 4 as the rotation center.

On the other hand, the force of the vertical arm drive source (motor) is transmitted to the vertical arm 2 via the vertical arm link 15, so that the vertical arm 2 is rotated about the vertical arm support bearing 3 (see FIG. 2). Rock.

In the first embodiment, a balance device 20 is provided in the casing 16 in order to balance the moment of the horizontal arm 5. In this balance device 20, the spring force of the torsion coil spring 21 is utilized to generate a moment on the side opposite to the work 7 with respect to the horizontal arm 5.

As shown in FIGS. 2 and 3, one end 21-1 of the torsion coil spring 21 has an engaging hole 12- of the drive shaft 12.
1 is inserted and engaged. On the other hand, torsion coil spring 2
The other end 21-2 of 1 is the groove 22 for springs of the adjustment flange 22.
-1 is inserted and engaged. The adjustment flange 22 has a plurality of elongated holes 22-2 formed in a line on the same circumference.
The adjustment flange 22 is fixed to the main body frame 1 by being fastened to the main frame 1. Therefore, the adjustment flange 22 has a long hole 22.
The mounting position in the circumferential direction can be adjusted by the amount of -2 in the circumferential direction.

The torsion coil spring 21 is previously attached by twisting it by a required angle. Therefore, the spring force of the torsion coil spring 21 increases the horizontal arm drive shaft 12 →
It is transmitted to the rear end (left end) of the horizontal arm 5 via the horizontal arm drive lever 11 → horizontal arm link lever shaft 10 → horizontal arm link 9 → horizontal arm link shaft 8. Moreover, the mounting direction of the torsion coil spring 21 is set so that the spring force of the torsion coil spring 21 produces a counterclockwise moment in the horizontal arm 5 in FIG. Therefore, a clockwise moment acting on the horizontal arm 5 (generated by the work 7 and a portion of the horizontal arm 5 on the right side of the axis 4) and a counterclockwise moment (spring force of the torsion coil spring 21 and the horizontal arm 5). (Caused by the portion on the left side of the shaft 4) and the driving force of the horizontal arm 5 can be reduced.

As the balance of the horizontal arm 5, the following modes can be selected by changing the set torsion angle of the torsion coil spring 21. A mode in which the spring force of the torsion coil spring 21 is adjusted so that the horizontal arm 5 becomes horizontal when the work 7 is gripped. In this mode, when the tip of the horizontal arm 5 is directed upward or downward, the spring force of the torsion coil spring 21 exerts a force for returning the horizontal arm 5 to the horizontal direction, and the driving force of the horizontal arm 5 is exerted. Therefore, the robot can be operated at high speed. However, when the work 7 is removed, the balance becomes excessive. A mode in which the spring force of the torsion coil spring 21 is adjusted so that the moment of the torsion coil spring 21 becomes half of the moment of the work 7. In this mode,
Excessive balance is reduced when the work 7 is removed.

After attaching the torsion coil spring 21,
The torsion angle of the torsion coil spring 21 can also be adjusted. That is, when the bolt 23 is loosened and the adjustment flange 22 is rotated by the length (circumferential length) of the slot 22-2, the torsion angle of the torsion coil spring 21 changes.
In this changed state, the bolts 23 are tightened again to fix the adjustment flange 22 to the main frame 1. With this configuration, the spring force of the torsion coil spring 21, and thus the torque for balancing can be easily adjusted even during the operation.

Since the torsion coil spring 21 is light in weight and has a small inertia and is arranged at the center of rotation, that is, between the horizontal arm drive shaft 12 and the adjusting flange 22, the torsion coil spring 21 moves with the movement of the horizontal arm 5. The part is small and the radius of gyration is small, and the increase of inertia can be minimized.

Here, a specific example of the effect obtained by balancing the moment of the horizontal arm 5 and the work 7 by the torsion coil spring 21 will be described. The joint length of the vertical arm 2 and the horizontal arm 5 is 0.
At 75 [m], the weight of the work 7 was 30 [kg], and the work 7 was reciprocated up and down 1 [m] 20 times per minute. In this state, when lifting the work 7,
Horizontal arm drive shaft 1 in total of inertia torque and mass torque
2 requires a torque of about 650 [N · m]. At this time, if a torque corresponding to half the mass of the horizontal arm 5 and the work 7 is generated by the torsion coil spring 21, the required torque is about 130 [Nm], that is, 20 [%].
Decrease.

Next, a second embodiment of the present invention will be described with reference to FIG. In the balance device 30 of the second embodiment, the force of the rotary actuator 31 is used to generate a moment (counterclockwise moment) on the side opposite to the moment of the work 7 with respect to the horizontal arm 5.

As shown in FIG. 4, a rotary actuator 31 is attached to an end plate 33 which is bolted to the fixing portion 32. The rotary shaft 31-1 of the rotary actuator 31 has a fitting hole 12- for the horizontal arm drive shaft 12.
2 is fitted and key-engaged.

When compressed air is supplied to the rotary actuator 31, the rotary shaft 31-1 rotates. Rotating shaft 31
The torque of -1 can be made variable by adjusting the air pressure of the compressed air supplied to the rotary actuator 31, for example, by adjusting the throttle of the pressure regulator.

The force of the rotary actuator 31 is transmitted to the horizontal arm 5 via the same path (horizontal arm drive link) as in the first embodiment, and produces a torque on the side opposite to the torque generated by the work 7 with respect to the horizontal arm 5. .

In the second embodiment, the force generated by the rotary actuator 31 can be adjusted arbitrarily and quickly by an external pressure regulator or the like, so that the movement (tilt) of the horizontal arm 5 and the weight of the work 7 can be adjusted. The force generated by the rotary actuator 31 can be easily and quickly adjusted according to the change. By doing so, the horizontal arm 5 can always be well balanced even during operation.

Although the rotary actuator 31 which operates by air pressure is used in the example of FIG. 4, a rotary actuator which operates by hydraulic pressure may be used.

[0031]

As described above in detail with the embodiments, in the present invention, the casing is provided with a balance device for producing a moment opposite to the moment produced on the tip side of the horizontal arm, and the torque of the balance device is provided. It is designed to be transmitted to the horizontal arm drive shaft. In other words, since the balance device is arranged at the center of rotation, the amount of movement of the balance device along with the movement of the horizontal arm is small.Therefore, without increasing the inertia or restricting the range of motion of the robot, The moment balance can be improved.

In the balance device using the torsion coil spring and the adjusting flange, the inertia of the torsion coil spring can be further reduced because the mass of the torsion coil spring is light, and the torque generated by the torsion coil spring can be adjusted by adjusting the position of the adjusting flange. .

Further, in the balance device using the rotary actuator, the torque can be easily adjusted by adjusting the supply fluid pressure.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an articulated robot to which a first embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view showing an AA cross section of FIG.

3 is a cross-sectional view showing a BB cross section of FIG. 2;

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional articulated robot.

[Explanation of symbols]

 01,1 Main body base 02,2 Vertical arm 3 Vertical arm support bearing 04,4 Horizontal arm support shaft 05,5 Horizontal arm 6 Work clamp hand 7 Work 08,8 Horizontal arm link shaft 09,9 Horizontal arm link 010,10 Horizontal Arm link lever shaft 011, 11 Horizontal arm drive lever 12 Horizontal arm drive shaft 12-1 Engagement hole 013 Weight 014 Tension spring 15 Vertical arm link 16 Casing 20 Balance device 21 Torsion coil spring 21-1 One end 21-2 The other end 22 Adjustment flange 22-1 Spring groove 22-2 Long hole 23 Bolt 30 Balance device 31 Rotary actuator 31-1 Rotating shaft 32 Casing 33 End plate

Claims (3)

[Claims] 1. A horizontal arm drive shaft provided in a casing, a vertical arm swingably provided with respect to the casing, and a swingably provided at the top of the vertical arm at the tip end side. A horizontal arm having a work, and a horizontal arm drive link for transmitting the driving force of the horizontal arm drive shaft to the rear end side of the horizontal arm to swing the horizontal arm,
A balancer for a multi-joint robot having: a torque that is provided in the casing and that generates a moment opposite to the moment generated at the tip of the horizontal arm, is applied to the horizontal arm drive shaft. A balance device for an articulated robot, characterized in that it is connected to a horizontal arm drive shaft. 2. A horizontal arm drive shaft provided in a casing, a vertical arm swingably provided with respect to the casing, and a swingably provided on the top of the vertical arm at the tip end side. A horizontal arm having a work, and a horizontal arm drive link for transmitting the driving force of the horizontal arm drive shaft to the rear end side of the horizontal arm to swing the horizontal arm,
A balance device provided in a multi-joint robot having: a horizontal arm driving device for applying a torque to a horizontal arm driving shaft to generate a torque that is opposite to a moment generated on the distal end side of the horizontal arm. The torsion coil spring connected to the shaft and the other end of the torsion coil spring are connected, and the torsion coil spring is attached to the casing in a state in which the attachment position can be adjusted along the rotation direction for adjusting the torsion angle of the torsion coil spring. A balance device for an articulated robot characterized by comprising an adjusting flange. 3. A horizontal arm drive shaft provided in a casing, a vertical arm swingably provided with respect to the casing, and a swingably provided on the top of the vertical arm at the tip side. A horizontal arm having a work, and a horizontal arm drive link for transmitting the driving force of the horizontal arm drive shaft to the rear end side of the horizontal arm to swing the horizontal arm,
A balance device provided for a multi-joint robot having: a torque that is provided in the casing and that produces a moment opposite to a moment produced at a tip side of the horizontal arm, is applied to the horizontal arm drive shaft. As described above, a balance device for an articulated robot characterized in that a rotary shaft for output is connected to a horizontal arm drive shaft and a rotary actuator whose output torque changes according to the pressure of a supplied fluid is provided.