Speaking of the driving angle of the
cam indexer, let’s talk about the working principle of the indexer. As a type of rotary device, the indexer is the input shaft that continuously rotates under the action of the motor as the driving source, so as to realize the intermittent, swing, lift or continuous output shaft. The indexing action of the same, the driving angle mentioned here, is only related to the force axis.
Theoretically speaking, a complete mechanical action is used to describe the drive angle. The input shaft rotates 360 degrees as a cycle. At this time, the output shaft completes a motion stop motion, and the motion of the output shaft is the input shaft. When completed, the angle of the output shaft rotation process is the driving angle. Therefore, when the input shaft rotates 90 degrees, the output shaft rotates one station, and the remaining 270 degrees is the angle of repose of the input shaft, which is also the stopping process of the output shaft. By analogy, when the driving angle is 120 degrees, 150 degrees, 180 degrees, 210 degrees, 240 degrees, 270 degrees, 300 degrees, 330 degrees, and 360 degrees, the corresponding angles of repose are 240 degrees, 210 degrees, 180 degrees and 150 degrees. Degrees, 120 degrees, 90 degrees, 60 degrees, 30 degrees, 0 degrees, etc., as shown below:
It can be seen from the above data that the input shaft rotates a circle is a constant value, and the continuous rotation speed of the input shaft driven by the motor is theoretically constant. In this way, the driving angle and the angle of repose of the input shaft rotation are generated The ratio of is also constant, which is what we call the dynamic-stop ratio of the output shaft. When the driving angle of the input shaft is 120 degrees, then the angle of repose is 240, then the dynamic-stop ratio is 1:2, and the indexer output shaft rotation time When it is 1 second, then the static time is 2 seconds, and when the driving angle of the input shaft is 180 degrees, the dynamic stop ratio of the output shaft is 1:1.
How to choose the driving angle? When selecting the drive angle, it is necessary to combine the actual use requirements. Speed and load are the factors that have a greater impact. When the curve is large, the slope of the curve is longer, and the curve of the rotating spiral groove of the cam is longer, so that the curve of motion is relatively smooth. At the intersection of the input shaft drive line and the stop line, the buffer force of the cam and the roller will be smoothly transitioned. , And when θh is small, the slope of the curve is steep, and there will be a greater impact at the intersection of the input shaft drive line and the stop line. Therefore, the larger the drive angle, the entire drive mechanism will run The more stable. Therefore, when choosing the drive angle, try to choose a larger drive angle to be more stable. For some high-speed indexers, such as 0.1 second and 0.2 second motion and stop conditions, the large driving angle will also affect the running speed of the indexer. Therefore, the quality of the indexer itself has higher requirements, such as the material of the cam and the processing. In actual use, high-speed operation system, due to improper selection of drive angle, indexer quality and other factors, the phenomenon of equipment operation jitter is more. For the situation where the speed requirement is not very high and the processing time is relatively long, it is recommended to choose a larger drive angle, because in this case, the stop angle of the output axis of the indexer in the automation system mostly needs to be equipped with an automatic control device .
In the above driving angle description, there is another case where the driving angle is 360 degrees, that is, the input shaft continuously rotates, and the output shaft does not stop. The
indexer here is actually a reducer function. In practical applications, Will use servo drive, combined with the stable operation of the indexer and the characteristics of large torque, to realize the positioning of any point.
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