JPS5959390A - Wrist section of industrial robot - 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 Field of Industrial Application The present invention relates to a wrist portion of an industrial robot.

Conventional structure and its problems Traditionally, the wrist of an industrial robot has been required to have high positional accuracy at the tip of the wrist, and due to the need for high-speed motion characteristics for robot function, the weight of the wrist, which is located at the tip of the arm, has generally been reduced. A system in which the drive source of the wrist and the harmonic reducer are directly connected, installed at the rear of the arm, and the output shaft of the harmonic reducer and one drive shaft of the wrist are driven using a transmission element such as a chain or timing belt. Or has been adopted. However, in method (7), the repeatability of the position at the tip of the wrist decreases due to stretching of the chain, timing belt, etc.
Problems such as the necessity of periodic maintenance, as well as the accuracy of the error between the most important teaching point and the reproduction position during playback operation in terms of playback robot function, and the accuracy of the reproduction position, The hysteresis characteristic of the element has an important meaning on the reproduction position accuracy, and when the hysteresis characteristic is a dog transmission element - even if the repeatable position accuracy is satisfied, the reproduction position accuracy is significantly reduced. Even in shaft drive systems, which are relatively rigid among transmission elements, compression rings are generally required due to the structure.
The above-mentioned hysteresis characteristic was noticeable in this coupling portion, and no improvement in the above-mentioned reproducibility accuracy could be expected. In order to improve the reproducible position accuracy compared to the past, an attempt was made to connect a single drive source and a harmonic reducer directly to the wrist. In the direct connection structure, the front part becomes large, and it was not possible to reduce the amount of N in terms of the motion characteristics.Objective of the InventionThe present invention solves the above problems, and achieves a small, lightweight, and highly accurate reproducible position. This provides 12 wrist parts that can be realized.

Structure of the Invention In order to achieve the above object, the present invention effectively utilizes conventional wrist components, without increasing the number of components significantly.
A harmonic reducer is inserted into the inner body of the wrist, and a drive source is placed at the rear of the wrist to transmit vertical force on the input side, which has little effect on accuracy. This allows the wrist to be made smaller, lighter, and has a higher positional accuracy.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a central sectional view, and FIG. 2 is a side view.

Rotation rotatably supported by the wrist body 1 via a bearing,
Output gears 4 and 5 are attached to the drive shaft 2 and the bending shaft 3, respectively, and the bending gear i3 is fixed to the swinging body 6. A rotating shaft rotatably supported via a bearing at one end is connected to the wrist end bracket 8 with a key and a tightening bolt. The input shaft 13 of the harmonic reducer is supported by a bracket fixed to the wrist body 1 with a small space outside the output gear 4.5 of the reducer.
．． 14 is arranged, and at the center of its input shaft 13 is a reducer web generator 16 and a tin rocket! or pulley 17
is fixed by a key. The input shaft 14 or pulley 18 is fixed, and the wrist front mechanism part 1/'i chain with the bending shaft 3 is connected to a belt 19 and a drive motor 21 and 20 to reduce the reduction ratio to about 1/100. is driven by. The rear end of the front part (the front part) is provided with a torsion 23 provided with a through hole for storing the drive cable, and is rotatably attached to the arm body 24 via a bearing.The rear end of the torsion!ll1l123 Followed by ll]ll i”J
The A part 25 is fixed, and is moved by a driving electric motor inside the arm and a vertical gear 26. In addition, 27.
28 is a potentiometer, 29 is a bracket for the motor take-up timer 1, 30 is a rotary encoder, 31 is a boden yometer, a driving gear, and 32 is a sprocket or a pulley.

Effects of the Invention As described above, the present invention realizes a compact, lightweight, highly accurate wrist configuration, and is effective in terms of cost since it does not require many parts, and the chain or belt on the input side has a high reduction ratio. There is no need for maintenance in terms of accuracy, and the configuration, which has two degrees of freedom for bending and rotation at the front of the wrist, and one degree of freedom for twisting at the rear of the wrist, has two degrees of freedom in terms of production. It also has a wrist part with 3 degrees of freedom and a freely selectable effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of a wrist portion of an industrial robot according to the present invention, and FIG. 2 is a side view of the same. 1...Wrist body, 2...Rotation 1 drive shaft, 3...Bending axis, 4, 5...Nomonic reduction gear output gear, 13.14... power shaft, 17.18° 32... sprocket size or pulley, 19,20... chain size or belt, 23... ...Twisted axis.

Claims (2)

[Claims] (1) The input Il+ of the harmonic reducer is provided in the bending shaft and the rotation shaft provided on the wrist body so that it can be freely rotated, and the output gear of the reduction gear is connected to the bending shaft and the rotation shaft. It is directly connected to the input shaft of the speed reducer, and a sprocket pulley is installed on the input shaft of the reducer. A wrist part of a robot for construction purposes. (2) The hand d portion of an industrial robot according to claim (1), wherein the rear twisting shaft of the wrist body is provided with a through hole inside the twisting shaft.