JP2699706B2 - Industrial robot equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot having an arm of a parallel link mechanism.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing a conventional parallel link type vertical articulated industrial robot apparatus. In the drawing, 1 is a main body base, 2 is a rotatable lower fixed base provided on the main body base 1, 3 is a first arm whose lower end is pivotally attached to the lower fixed base 2, and 4 is a first arm 3. A driving motor (second shaft) 5 is stretched between the first arm 3 and the lower fixed base 2 to compensate for the gravity of the first arm 3.
The arm springs 6 are back links whose lower ends are pivotally connected to the lower fixed base 2 and are arranged side by side with the first arm 3.

An upper link 7 is pivotally connected to the upper ends of the first arm 3 and the back link 6. A second arm drive motor (third shaft) 9 is pivotally connected at one end to an upper rear portion of the upper link 7.
The lower arm 10 has one end pivotally connected to the connecting portion between the back link 6 and the upper link 7 and is arranged side by side with the second arm 8 so as to be vertically swingable,
Reference numeral 11 denotes a front link pivotally connected to the other ends of the second arm 8 and the lower link 10, 12 denotes a wrist shaft connected to the front link 11, and 13 denotes a second arm fixed to the rear end of the second arm 8. An equilibrium weight for gravity compensation of the arm 8.

[0004] The conventional industrial robot apparatus is configured as described above, and the first arm 3 is attached to the lower fixed base 2.
Rotating around the second shaft 4, the upper link 7 is always kept horizontal by the parallel link constituted by the first arm 3 and the back link 6 irrespective of the rotation of the second shaft 4. The second arm 8 rotates around the third shaft 9 with respect to the upper link 7. The wrist shaft 12 is always held vertically by the parallel link constituted by the second arm 8 and the lower link 10 irrespective of the rotation of the third shaft 9. Thus, the wrist shaft 12 is always kept horizontal without being affected by the rotation of the second shaft 4 and the third shaft 9.

[0005]

In the above-mentioned conventional industrial robot apparatus, since the equilibrium weight for gravity compensation is provided behind the second arm 8, when the robot is evacuated backward, the weight is reduced. If the projection amount is large and has a plurality of operation areas, there is a risk of interference with peripheral devices. In addition, there is a problem that the motor 9 for driving the second arm 8 becomes large due to an increase in the moment of inertia due to the load.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has been made without reducing the operation area.
It is an object of the present invention to provide an industrial robot device capable of miniaturizing a motor for driving an arm.

[0007]

According to the present invention, there is provided an industrial robot apparatus comprising a flat arm including a first arm and a back link.
A drive motor having a row link and a robot arm formed of a parallel link consisting of an upper link, a second arm, a lower link, and a front link, wherein the upper link swings the second arm up and down; A state in which a spring is stretched between the upper link and the pivotal joint of the second arm and the front link and the pivotal joint of the lower link, and the force of this spring is applied to the robot arm in a horizontal posture Is set to balance with the gravity acting on the robot arm.

[0008]

In the present invention, since a spring is stretched between the upper link and the pivot of the second arm and between the front link and the lower link, there is no projecting member to the rear of the arm.
The moment of inertia can be minimized. Also, since the spring force is set to be balanced with the gravity when the robot arm is horizontal, the spring is balanced at the most frequently used horizontal position.

[0009]

1 to 4 show an embodiment of the present invention. FIG. 1 is a side view, FIG. 2 is a detailed view of a main part of FIG. 1, FIG. 3 is a plan view of FIG. 2 , and FIG. FIG. 4 is a detailed view of a main part of FIG.

In the drawing, reference numeral 21 denotes a tension spring which is stretched between a pivot portion between the upper link 7 and the second arm 8 and a pivot portion between the front link 11 and the lower link 10. The force of the pulling spring 21 is set so as to balance with the load caused by the weight of the wrist shaft 12 and the work (not shown) when the second arm 8 is in the horizontal posture.

In the industrial robot apparatus configured as described above, the motor 9 is driven and the second arm 8 is
As shown in (2), the amount of tension of the tension spring 21 decreases, and the driving torque of the motor 9 increases due to the weight of the wrist shaft 12 and the work. When the second arm 8 rotates downward, all the loads due to the weight of the wrist shaft 12 and the work are canceled, and the tension spring 21
Therefore, a force for pulling the pulling spring 21 is generated as a driving torque of the motor 9.

In this manner, since there is no projecting member behind the second arm 8, the interference area when the robot performs the retreat operation is reduced. Further, since the moment of inertia can be minimized, the size of the motor 9 can be reduced. Further, since the tension spring 21 and the gravity are balanced at the most frequently used horizontal position for the convenience of the robot, the motor 9 at that time is balanced.
Has a small holding current and saves energy.

[0013]

As described above, according to the present invention, a spring is stretched between the upper link and the pivot of the second arm, and between the front link and the lower link. Since the spring is stretched, there is no projecting member to the rear of the arm, so that it is possible to prevent the operation area from being reduced, and to achieve the effect of minimizing the motor by minimizing the moment of inertia. Further, since the spring force is set to be balanced with the gravity when the robot arm is horizontal, the spring is balanced at the most frequently used horizontal position, which has an effect of energy saving.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a detailed view of a main part of FIG. 1;

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a detailed view of a main part of FIG. 3;

FIG. 5 is a side view showing a conventional industrial robot device.

[Description of Signs] 2 Lower fixed base 3 First arm 6 Back link 7 Upper link 8 Second arm 9 Second arm drive motor 10 Lower link 11 Front link 12 Wrist shaft 21 Tension spring

Claims (1)

(57) [Claims] A lower end is pivotally attached to a lower fixed base.
Parallel link consisting of the first arm and the back link
A, and the upper end to the pivotally mounted the upper link of the first arm and the back link, a second arm and lower link having one end pivotally connected to the upper and lower portion of the upper link, respectively, the second arm and A drive motor having a robot arm formed of a parallel link consisting of a front link connected to the other end of the lower link and connected to the wrist axis, and the upper link swinging the second arm in the vertical direction; Wherein a spring is stretched between the upper link and the pivot of the second arm and between the front link and the lower link, and the force of the spring is applied by the robot arm to the horizontal. An industrial robot apparatus which is set to be in equilibrium with gravity acting on the robot arm in a posture.