The feature of planetary gearbox for stepper motors

Compared with ordinary gear drives, planetary gearbox for stepper motor have many characteristics. The main characteristics of planetary gear transmissions are as follows:

1. Small size, small mass, compact structure, and high load-bearing capacity. This is a common shaft due to the drive and power distribution of the planetary gearbox, as well as the transmission of the central wheel and the reasonable application of internal meshing gears.

2. Drive efficiency. This is because of the symmetry of the planetary gear drive structure. As is well known, there are many types of stepper motor planetary gearboxes. The reaction force of the minute wheel and the rotating arm can be balanced, which is beneficial for transmission efficiency. If the selected driver type is suitable and the structure is reasonable.

3. Comparison of large drives. The drive is larger than a planetary gearbox, and can still maintain the characteristics of compact structure, small volume, and small volume. It can also achieve synthetic decomposition motion and various complex movements. As long as the type of planetary gearbox and distribution scheme is appropriately selected, planetary gears can be achieved through synthesis and motion decomposition, and variables can be used to obtain a large number of gear ratios.

4. The planetary gearbox adopts the same planetary gears, with evenly distributed center wheels, allowing the planetary gears and force balancing arms to move simultaneously, ensuring the stability of the planetary gearbox. At the same time, with the addition of teeth, planetary gears move stably, with stronger impact resistance and vibration resistance, making their work more reliable.

The planetary gear set, also known as a planetary gearbox or planetary reducer, is mainly used to reduce input speed, output low speed, and increase torque to achieve ideal transmission effect.

Advantages:

1. High efficiency: The transmission efficiency of planetary gears can reach over 90%.

2. High precision: The compact structure of planetary gears can effectively ensure the stability of transmission accuracy.

Application: 

Planetary gearboxes are widely used, initially in conjunction with electric motors. In addition to being used for micro reduction motors, they are also used in the shading industry, office automation, smart home, production automation, medical equipment, financial machinery, game consoles, and other fields. For example, in industries such as automatic curtains, intelligent toilets, lifting systems, cash registers, advertising lightboxes, and so on.

Source: https://www.steppernews.com/2023/08/the-feature-of-planetary-gearbox-for_18.html

The advantages and disadvantages of integrated stepper motors

The stepper motor driver and motor can be integrated into one unit, which is an integrated motor. The manufacturer provides various combinations of integrated stepper motor driver combinations, each with its own advantages and disadvantages.

 

 

 

The advantages of integrated stepper motors include easy placement, reduced wiring complexity, faster system setup and construction, and motor driver compatibility. In addition, an integrated unit integrating the control system is also provided.

 

Easy on-site layout may be the most significant advantage of integrated motors. They do not require wiring between the driver and motor, and can be easily placed in the appropriate location and connected to the controller. This means that settings can be made faster to transition the motion control system from design drawings to production time in a short period of time.

 

Meanwhile, reducing wiring complexity means that engineers do not have to worry about whether the input and output are correctly connected between the driver and motor. Unipolar or bipolar wiring is no longer an issue. Similarly, interference between cables is reduced, and communication is greatly enhanced.

 

 

Integrated motors also mean good compatibility between the motor and driver. It can be used together for they are provided together by the manufacturer. It can reduce the workload during the torque speed curve, as these have already taken into account the drive. For example, there is no need to worry about whether the driver provides the correct type of signal or uses the correct voltage, as all of these have been resolved. If the integrated unit comes with controls, it may be simpler and can handle most control operations. Meanwhile, the merged units can now be connected to other units, which is particularly useful in the Internet of Things.

 

The main drawback of this setting is the lack of implementation flexibility and potential supplier chain, which leads to troubleshooting issues and equipment maintenance changes. Because the drive motor combination is a unit, it is usually only applicable to certain applications and not to other applications. In addition, if the driver needs to be replaced but the motor is functioning properly, the entire unit can only be replaced.

What is Best Choice Between Servo Motor and Stepper Motor？

 Servo Motor vs Stepper Motor: Which is right for your application?

It is an engineering truism that there is no perfect solution, just the best solution for the problem at hand. That holds particularly for servo motors and stepper motors. Both are broadly used in industry. Neither is a universal solution. When properly applied, however, both stepper motor and servo motor can provide effective, reliable power for a highly successful system. The decision tree for choosing between the two has many branches but the most important are speed, acceleration, and price target.

 

Stepper Motors
Stepper motors consist of a rotor with permanent magnets and a stationary stator that carries the windings. When current runs through the stator windings, it generates a magnetic flux distribution that interacts with the magnetic field distribution of the rotor to apply a turning force. Stepper motors feature very high pole counts, typically 50 or more. The stepper motor driver energizes each pole in sequence so that the rotor turns in a series of increments, or steps. Because of the very high pole count, the motion appears to be continuous.

Stepper motors have a number of positive attributes. Because they generate incremental motion, they are generally run open loop, eliminating the cost and complexity of an encoder or resolver. The high pole count allows them to generate very high torque at zero speed. They are compact and generally economical.

Stepper Motor
Figure 1: Stepper motors deliver good performance at an economical price point for applications requiring low speed, acceleration, and accuracy. (Courtesy of Kollmorgen)

On the downside, stepper motors have speed limitations. They generally run best at 1200 RPM or lower. Although they generate high torque at zero speed, torque falls off as speed increases (see figure 2). A motor that generates 100 ounce inches at zero speed might only deliver 50 ounce inches at 500 RPM, for example, and just 10 ounce inches at 1000 RPM. In theory, a gearbox could be used to increase torque, but this is where the low speed of stepper motors becomes a problem. Adding a 10:1 gear reducer to a 1200 RPM stepper motor might boost the torque by an order of magnitude but it will also drop the speed to 120 RPM. If the motor is being used to drive a ball-screw actuator or similar, it probably will not deliver sufficient speed to satisfy the needs of the application.

Stepper motors generally are not available in frame sizes larger than NEMA 34, with most applications falling in the NEMA 17 stepper motor or NEMA 23 stepper motor sizes. As a result, it is unusual to find stepper motors capable of producing more than 1000 to 2000 ounce inches of torque.

Stepper motors also have performance limitations. You can think of a stepper motor as a spring-mass system. The motor needs to break friction to begin turning and move the load, at which point the rotor is not fully controlled. As a result, a command to advance by five steps may only result in the motor turning four steps – or six. If the drive commands a motor to advance 200 steps, however, it will do so to within just a few steps, which at that point represents an error of a few percent. Although we command stepper motors with a resolution of typically between 25,000 and 50,000 counts per revolution, because the motor is a spring-mass system under load, our typical resolution is 2000 to 6000 counts per revolution. Still, at these resolutions, even a 200-step move corresponds to a fraction of a degree.