1. Reasons for stepper motors with gearboxes
The stepper motor switches the frequency of the stator phase current, such as changing the input pulse of the stepper motor drive circuit, so that it becomes a low-speed movement. Low-speed stepping motor waiting for stepping instructions, the rotor is in a state of stop, in the low-speed stepping, speed fluctuations will be large, at this time, such as changing to high-speed operation, can solve the problem of speed fluctuations, but the torque will be insufficient. That is, low-speed torque fluctuations, and high-speed torque will be insufficient, so the need to use a reducer.
2. Stepping motor often with what reducer
Reducer is a kind of independent parts composed of gear transmission, worm gear transmission and gear-worm transmission enclosed in a rigid shell, which is often used as a deceleration transmission device between the prime mover and the working machine, and plays the role of matching the rotational speed and transmitting the torque between the prime mover and the working machine or the actuator;
There are many kinds of reducers, which can be divided into gear reducer, worm reducer and planetary gear reducer according to the type of transmission, and single-stage and multi-stage reducers according to the number of transmission stages;
According to the shape of the gear can be divided into cylindrical gear reducer, bevel gear reducer and cone - cylindrical gear reducer;
According to the form of transmission arrangement can be divided into the expansion type reducer, shunt type reducer and coaxial type reducer.
Stepping motor assembly reducer planetary reducer, worm gear reducer, parallel gear reducer, screw gear reducer.
What about stepper motor planetary gearhead precision?
Gearhead precision is also known as the return clearance, the output is fixed, the input is rotated clockwise and counterclockwise, so that when the output produces the rated torque +-2% torque, the input of the gearhead has a small angular displacement, this angular displacement is the return clearance. The unit is "arc minute", i.e. one sixtieth of a degree. The usual return clearance value refers to the output side of the gearhead.
Stepping motor planetary gearbox has the characteristics of high rigidity, high precision (single stage can be achieved within 1 minute), high transmission efficiency (single stage in 97%-98%), high torque/volume ratio, maintenance-free and so on. Public number "Mechanical Engineering Literature", the engineer's petrol station!
The transmission precision of the stepper motor can not be adjusted, the operating angle of the stepper motor is completely determined by the step length and the number of pulses, and the number of pulses can be counted in full, the digital quantity does not exist in the concept of precision, one step is one step, and two steps are two steps.
At present, the precision that can be optimised is the precision of the gear return gap of the planetary reducer gearbox:
1. Spindle precision adjustment method:
Adjustment of the rotation accuracy of the planetary reducer spindle, if the machining error of the spindle itself meets the requirements, then the rotation accuracy of the reducer spindle is generally determined by the bearings.
The key to adjusting the rotary accuracy of the spindle is to adjust the bearing clearance. Maintaining an appropriate bearing clearance is critical to the performance of spindle components and bearing life.
For rolling bearings, when there is a large clearance, not only will the load concentrate on the rolling body in the direction of the force, but also in the bearing inner and outer ring raceway contact to produce a serious stress concentration phenomenon, shorten the bearing life, but also make the spindle centre line drift, easy to cause vibration of the spindle parts.
Therefore, the adjustment of rolling bearings must be pre-loaded, so that the bearing internal generation of a certain amount of surplus, so as to produce a certain amount of elastic deformation in the rolling body and the inner and outer ring raceway contact, so as to improve the stiffness of the bearing.
2. Adjustment of clearance method:
Planetary reducer in the process of movement will produce friction, causing changes in the size, shape and surface quality between the parts, and produce wear and tear, so that the clearance between the parts with increased, at this time we need to make a reasonable range of adjustments to ensure the accuracy of the relative movement between the parts.
3. Error compensation method:
The parts of their own errors through proper assembly, so that the phenomenon of mutual offset during the break-in period to ensure the accuracy of the equipment movement trajectory.
4. Comprehensive compensation method:
Use the reducer itself to install the tools to make the processing has been transferred to match the adjustment of the correct and error-free worktable, in order to eliminate the combined results of the various accuracy errors.
Post time: Jul-04-2024