JP2017007000A - Transfer arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem that a transportation arm of a robot having two or more joints according to a conventional technique is not appropriate for high speed operation or rotation and stop positions of the arm cannot be controlled with high precision.SOLUTION: A first arm and a second arm coupled to each other are driven by a first power source and a second power source, respectively and independently of each other. A first rotary shaft driven by the first power source is coaxial with a second rotary shaft driven by the second power source, the first arm is directly connected to the first rotary shaft and driven, rotation of a first drive shaft connected to the second rotary shaft is transferred to a second drive shaft of a joint part between the first arm and the second arm by a connecting rod, and the second arm is driven by rotation of the second drive shaft to which the rotation of the first drive shaft is transferred.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transfer arm mechanism used in a robot having two or more joints, for example.

  Articulated robots are often used in parts transportation and assembly. For example, in a transfer arm of a two-joint robot, the two connected arms are rotated in conjunction with each other, and the second arm at the tip is quickly moved to a predetermined position, where the above operation is performed. As a drive mechanism for that purpose, a drive mechanism (motor, speed reducer, etc.) is conventionally provided for each joint of the first arm and the second arm that are connected, such as a transfer arm disclosed in Patent Document 1, for example. What is common is. Also, as disclosed in Patent Document 2, for example, the first arm is directly driven by a motor at the base end, whereas the second arm timings the power of this motor via a speed reducer and a pulley. It is also common to transmit to the belt and thereby drive the rotating shaft at the base end of the second arm.

JP 2010-46733 A JP 2011-56844 A JP-A-11-207684

  However, since the transport arm of the type in which the drive mechanism is provided for each joint of the two arms includes the second drive mechanism having a large weight at the base end portion of the second arm away from the rotation axis of the first arm, When rotating the first arm, the inertia of the second arm is large, which is not suitable for high-speed operation.

  On the other hand, the transport arm of the type in which the second arm is driven by the timing belt has the advantage that only one power source is required. However, even if the rotational force of the power source is directly transmitted to the first arm, the second arm Because the transmission to the rotating shaft is transmitted via the timing belt, the positioning belt positioning accuracy is lowered due to the low transmission rigidity of the timing belt, and backlash on the rotating shaft is likely to occur. was there.

  The present invention is to solve such a problem, and the object thereof is to control the rotation of the connected first arm and second arm with high accuracy and to use the individual rotation shafts of both arms. It is an object of the present invention to provide a transfer arm mechanism that can suppress backlash.

The present invention relates to a transfer arm that solves the above-described problems, and is configured as follows.
First and second arms connected to each other, a first power source for driving the first arm, a second power source for driving the second arm, and a base for supporting them A transfer arm mechanism,
A first rotating shaft driven by the first power source; and a second rotating shaft driven by the second power source;
The first rotating shaft and the second rotating shaft are coaxial, and coincide with the rotation center of the first arm and extend to the base end of the first arm;
The first arm is coupled to the first rotation shaft and rotates in conjunction with the first rotation shaft;
A first drive shaft coupled to a tip of the second rotation shaft; a second drive shaft coupled to the second arm at a joint of the first arm and the second arm; and the first drive shaft. A transmission element for connecting the second drive shaft to transmit power;
The first drive shaft converts the rotational motion of the second rotating shaft into a reciprocating motion of the transmission element; the second drive shaft reconverts the reciprocating motion of the transmission element into a rotational motion;
The second arm is configured to rotate in conjunction with the rotational movement of the second drive shaft.

  In the transfer arm mechanism according to the present invention, preferably, the transmission element is formed of a highly rigid member.

  In the transfer arm mechanism according to the present invention, it is more preferable that the transmission element is a connecting rod or a highly rigid timing belt.

  By adopting such a configuration, since the second power source is not attached to the second arm, the inertia inertia during the rotation of the first arm can be reduced. The first arm is directly driven by a first rotating shaft directly connected to the first power source, and the second arm is connected to a connecting rod or a first driving shaft coupled to the second rotating shaft directly connected to the second power source. It is driven by a second drive shaft to which a driving force is transmitted using a highly rigid member such as a highly rigid timing belt. Therefore, rotation and stop of each arm can be controlled at high speed and with high accuracy by each power source, and backlash on the rotation shaft of each arm can be reduced.

  Further, since the first arm and the second arm can be independently rotated by the first power source and the second power source, respectively, it is complicated to drive the first arm and the second arm in conjunction with each other. It is not necessary to add a special mechanism, and the drive control device can be simplified, so that the transport arm mechanism can be reduced in size.

  Furthermore, in the present invention, the rotation center axes of the first power source and the second power source are not coaxial with each other because the first rotation shaft and the second rotation shaft disposed on the same axis are not coaxial. As in the case of a mechanism in which the shaft and the first and second rotating shafts coincide with each other (for example, Patent Document 3), it is not necessary to devise specially the supply wiring to the two power sources, and the first and second power There is also an advantage that the design freedom of the source is great.

It is sectional drawing of the arm mechanism for conveyance by 1st Example of this invention. It is sectional drawing of the arm mechanism for conveyance by 2nd Example of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a transfer arm mechanism according to a first embodiment of the present invention. In the transfer arm mechanism 100, a first rotating shaft 112 on which a first power source (servo motor) 111 is driven via a speed reduction mechanism (roller drive mechanism) is installed on a base 101 in the lateral direction, and further a second power source. A second rotating shaft 122 driven by a (servo motor) 121 via a speed reduction mechanism (roller drive mechanism) is disposed coaxially inside the first rotating shaft 112. The base end portion of the first arm 110 is fixed to the distal end portion of the first rotating shaft 112, and the first arm 110 rotates in conjunction with the rotation of the first rotating shaft 112. In this embodiment, the roller drive mechanism is used as the speed reduction mechanism. However, another mechanism such as a worm gear may be used, or the second rotating shaft may be directly connected to the power source without using the speed reduction mechanism.

  On the other hand, a first drive shaft 131 is attached to the distal end portion of the second rotating shaft 122 extending to the base end portion of the first arm 110, and a high-rigidity timing belt 132 is provided on the outer periphery thereof as a power transmission element. The rotation of the second rotating shaft 122 is transmitted to the high-rigidity timing belt 132. A joint portion 136 that couples the first arm 110 and the second arm 120 is provided with a second drive shaft 133, a high-rigidity timing belt 132 is attached to the outer periphery thereof, and the rotation of the second rotation shaft 122 is second. It is transmitted to the drive shaft 133. A second arm 120 is fixed to the second drive shaft 133, and the second arm 120 rotates in conjunction with the rotation of the second rotation shaft 122.

  FIG. 2 is a sectional view of a transfer arm mechanism according to the second embodiment of the present invention. In the transfer arm mechanism 200, a first rotating shaft 212 driven by a first power source (servo motor) 211 via a speed reduction mechanism (roller drive mechanism) is installed in the vertical direction, and further a second power source (servo motor). A second rotating shaft 222 that is driven by a gear 221 via a gear is arranged coaxially inside the first rotating shaft 212. A first arm 210 is fixed to the tip of the first rotating shaft 212, and the first arm 210 rotates in conjunction with the rotation of the first rotating shaft 212. In this embodiment, the roller drive mechanism is used as the speed reduction mechanism of the first power source, but other mechanisms such as a worm gear may be used. Moreover, although the 2nd power source and the 2nd rotating shaft are couple | bonded via the gear, it is good also as a direct connection.

  On the other hand, a first drive shaft 231 is fixed to the tip of the second rotation shaft 222, and a connecting rod 232 is connected to a crank 233 on the outer periphery thereof as a power transmission element, and the rotation of the second rotation shaft 222 is connected to the connecting rod. It is converted into the rotation / reciprocation of. A second drive shaft 237 is attached to the joint portion 236 that connects the first arm 210 and the second arm 220, and the distal end portion of the connecting rod 232 is connected to the crank 235 on the outer periphery of the second drive shaft 237. The reciprocating motion is converted again into the rotational motion of the second drive shaft 237. The intermediate crank 234 is for rotating the first drive shaft 231 and the second drive shaft 237 in the same phase. In this embodiment, the second arm 220 rotates coaxially with the second drive shaft 237, and although not shown, various attachments can be attached to the second arm 220.

  Although the above description has been made with reference to the embodiments, the present invention is not limited thereto, and it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit of the present invention and the scope of the appended claims. It is.

100, 200 Transfer arm mechanism 101 Base 110, 210 First arm 111, 211 First power source 112, 212 First rotating shaft 120, 220 Second arm 121, 221 Second power source 122, 222 Second rotating shaft 131, 231 First drive shaft 132 High-rigidity timing belt 133, 237 Second drive shaft 136, 236 Joint portion 232 Connecting rod 233, 234, 235 Crank

Claims (4)

First and second arms connected to each other, a first power source for driving the first arm, a second power source for driving the second arm, and a base for supporting them A transfer arm mechanism,
A first rotating shaft driven by the first power source; and a second rotating shaft driven by the second power source;
The first rotating shaft and the second rotating shaft are coaxial, and coincide with the rotation center of the first arm and extend to the base end of the first arm;
The first arm is coupled to the first rotation shaft and rotates in conjunction with the first rotation shaft;
A first drive shaft coupled to a tip of the second rotation shaft; a second drive shaft coupled to the second arm at a joint of the first arm and the second arm; and the first drive shaft. A transmission element for connecting the second drive shaft to transmit power;
The first drive shaft converts the rotational motion of the second rotating shaft into a reciprocating motion of the transmission element; the second drive shaft reconverts the reciprocating motion of the transmission element into a rotational motion;
The transfer arm mechanism is configured such that the second arm rotates in conjunction with the rotational movement of the second drive shaft.   The transfer arm mechanism according to claim 1, wherein the transmission element is a highly rigid member.   The transfer arm mechanism according to claim 2, wherein the rigid member is a connecting rod. The transfer arm mechanism according to claim 2, wherein the highly rigid member is a highly rigid timing belt.