JPS6348671B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a robot used for various industrial applications, and more particularly to a joint structure in a robot having a rotating arm and a joint structure between the rotating arm and a robot base or between adjacent arms. .

2. Description of the Related Art Robots having articulated arms similar to those seen in the human body and a hand portion at the tip of the arm have been widely used in recent years to grasp and transport objects and perform certain tasks using the objects. That is, it has advantages such as saving labor in manual work and performing high-speed work and high-load work in cooperation with manual work. Drive sources such as hydraulic actuators, pneumatic actuators, or electric motors are generally used to drive the arm or hand of such robots, but robots used for household use, office processing, etc. are easily driven by electric motors. This is especially advantageous in terms of introducing it as a drive source because it can be driven simply by connecting it to a power outlet.
Furthermore, in robots that use an electric motor as a drive source, it is common to have a structure in which the driving force is transmitted from one electric motor to multiple arm actuating parts using a gear mechanism, belt/pulley mechanism, steel cable, etc.; According to the above, the operation of an arm or hand located far from the drive electric motor is disadvantageous in terms of high-speed and high-precision positioning. Therefore, in order to overcome this disadvantage, a robot having a structure in which one electric motor is attached to each joint of the robot to drive each arm has already been proposed. However, robots with this latter joint structure have the disadvantage that each joint inevitably becomes larger because a structure is adopted in which a motor with an appropriate output specification is externally mounted on each joint.

Therefore, an object of the present invention is to provide a joint structure for a robot that can take advantage of the structure in which each joint is provided with one electric motor to drive the arm or hand, while also eliminating the drawbacks of the above-mentioned large size. be.

That is, according to the present invention, in view of the above-mentioned object, each joint structure of the robot is formed as a pivoting structure equipped with a rotation bearing, and the pivoting structure itself is provided with an electric motor function. It is something. Hereinafter, the present invention will be explained in more detail based on embodiments shown in the accompanying drawings.

FIG. 1 is a front view showing an example of the configuration of a conventional robot in which each joint structure is equipped with one electric motor, which is the premise of the present invention, and this example shows a robot having two-stage arms. Now, this robot has base 1.
An electric motor MA1 for driving the first stage arm 16 is mounted above a joint 14 provided on the bracket 12 of the motor 1, and the driving force of the electric motor MA1 is transmitted via a belt/pulley mechanism 18. That is, the first stage arm 16 pivots in the direction indicated by arrow A at the joint 20. Further, another electric motor MA2 is mounted above the joint 20 of the first stage arm 16, and the driving force of this electric motor MA2 is transmitted to the second stage arm 24 via a belt/pulley mechanism 22. The double arm 24 pivots in the direction shown by arrow B together with its bracket 24a. The second stage arm 24 is also configured to rotate in the direction of arrow C by the electric motor MA3.
A hand 26 is provided at the tip of the hand 26.
An article (not shown) such as a power tool is gripped by the elastic gripping force of a leaf spring 30 provided in the gripping space 28 . Also electric motor
Encoders 32 and 3 are installed at the top of each of MA1 and MA2.
4 is provided. That is, these encoders 32 and 34 are configured with rotation detection discs 32a and 34a and detection signal detection devices 32b and 34b, and detect the amount of rotation of each motor shaft to detect the first stage arm 16 and The amount of movement with respect to the second stage arm 24 can be detected. 32c, 34c
is a detection signal sending line. As is clear from the configuration of this robot, all of the electric motors MA1 to MA3 are mounted on the joint structure and are arranged in a state of protrusion to the outside, so as mentioned above, each joint structure becomes large. , it has the disadvantage of lack of compactness.

FIGS. 2 and 3 are an external three-dimensional view and an exploded view of a robot joint structure according to the present invention, which has been newly devised to overcome the disadvantages caused by the large size of the conventional robot joint structure, In particular, it representatively shows the joint structure provided between adjacent arms.
As is clear from FIGS. 2 and 3, according to the present invention, a pivot joint structure 44 is provided between the first arm 40 and the second arm 42, and the pivot joint structure 44 is electrically powered. The pivot joint structure 44 incorporates a motor 46.
It is formed so that it itself has a drive motor function. As clearly shown in FIG. 3, the electric motor 46 has upper and lower bearing members (for example, end bell type rolling bearings) 48, 48 fixed to the first arm 40 and a stator 50 having an excitation coil 52; The second arm 42 is formed by fixing a shaft 54 and an armature 58 made of a permanent magnet 56.
That is, by supplying an excitation current to the excitation coil 52 of the stator 50, the armature 58 is made to perform its normal motor function of generating rotational force, and the bearing member 4
8 and 48, a relative pivoting action is generated between the first stage arm 40 and the second stage arm 42. As is clear from the above-described structure and operation, the joint structure of the robot according to the present invention has no structure protruding to the outside in the joint structure portion 44, and the joint structure itself has a motor function, so that it can be made smaller and lighter. Both have the same effect. Furthermore, it is extremely preferable to form the above-mentioned electric motor 46 as a slotted wire-type DC motor because the required output amount and torque per unit weight can be easily controlled by controlling the amount of supplied current. Although the electric motor 46 shown in FIG. 3 is an example of a brushless motor, a bearing member 48' having a brush holder 49 as shown in FIG. It is also possible to form a brush motor by replacing the stator 50' with the stator 50 described above and fixing it to the first stage arm 40, and further replacing the armature 58 described above with an armature 58' with an excitation coil. . Further, if the electric motor 46 is formed as a pulse motor, the relative pivot amount between the first stage arm 40 and the second stage arm 42 can be easily controlled by pulse input.

As explained above, the joint structure of the robot according to the present invention includes one pivot shaft rotatably supported,
a second arm that is provided so as to be able to receive rotational force from near both ends of the pivot shaft and rotates around the pivot shaft as the pivot shaft rotates; and a second arm that is held by the second arm near both ends of the pivot shaft. , a first arm that is rotatable about the pivot axis relative to the second arm;
and an electric motor that includes a stator and a rotating armature and rotationally drives the pivot shaft, the first and second arms being relatively rotatable about the pivot shaft by the electric motor. In the joint structure of the robot, the rotary armature is fixed around the entire circumference near the center of the pivot shaft, the pivot shaft also serves as the rotation shaft of the electric motor, and the stator is The rotary armature is fixed to the first arm so as to cover the entire circumference of a rotating armature fixed over the entire circumference of the pivot, and the first and second arms are moved relative to each other around the pivot by the electric motor. The first feature is that it can be rotated.
Since the second arm can be used as a motor case and the shaft end does not protrude outside the arm, the joint structure can be made smaller.

Although the above example shows an example of a joint structure provided between adjacent arms, it is also possible to form a similar joint structure between the robot base and the arm and between the arm and the hand. It goes without saying that it is possible. As the joint structure becomes smaller and lighter, the robot itself becomes smaller and lighter, and especially in the case of robots for home use or office processing, the simplicity of the external structure makes it possible to give the robot itself a smart appearance. It is. Further, according to the present invention, since the rotating armature is fixed around the entire circumference of the pivot shaft and the stator is fixed so as to cover the rotating armature, a large force can be generated. It becomes possible to generate sufficient force for relative rotation of the arm and the second arm with a small and lightweight structure.

[Brief explanation of drawings]

Fig. 1 is a front view showing a representative configuration example of a conventional multi-stage arm type robot, Fig. 2 is an external three-dimensional view of an embodiment of the robot joint structure according to the present invention, Fig. 3 is an exploded view of the same, and Fig. 4 is an exploded view of the robot. FIG. 7 is a three-dimensional diagram of each element for explaining another embodiment. DESCRIPTION OF SYMBOLS 10... Base body, 16... First stage arm, 18... Second stage arm, 40... First arm, 42... Second arm, 44... Joint structure part, 46... Electric motor, 50... Stator, 52...
Armature.

Claims (1)

[Claims] 1. A rotatably supported pivot; a second arm that is provided to receive rotational force from near both ends of the pivot and rotates about the pivot as the pivot rotates; The second
a first arm that is held in an arm and is rotatable around the pivot shaft relative to the second arm; and an electric motor that rotationally drives the pivot shaft, including a stator and a rotating armature. In the joint structure of the robot, the rotary armature is arranged around the entire circumference of the rotary armature near the center of the pivot shaft. The rotary armature is fixed over the entire circumference of the pivot shaft, and the stator is configured such that the pivot shaft also serves as a rotating shaft of the electric motor, and the stator covers the entire circumference of the rotating armature that is fixed over the entire circumference of the pivot shaft. Said first
A joint structure for a robot, wherein the joint structure is fixed to an arm of a robot, and the first and second arms are relatively rotatable about the pivot axis by the electric motor.