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Stepper motor planetary gearbox

Stepper motor planetary gearbox

The stepper motor planetary gearbox  is mainly constructed with a sun gear, a planetary gear, an inner ring gear and a planet carrier.

   In order to evenly distribute the loads of the three planet wheels, a toothed floating mechanism is used, that is, the sun gear or the planet carrier floats, or both the sun gear and the planet carrier float at the same time. The gears in the stepper motor planetary gearbox are straight-tooth involute cylindrical gears. Has the following characteristics:

  1. Small in size and light in weight. Under the same conditions, it is 1/2 or more lighter than the ordinary involute cylindrical gearbox , and the volume is 1/2 to 1/3.

    2, the transmission efficiency is high: single-stage stepper motor planetary gearbox reaches 97% ~ 98%; two-stage stepper motor planetary gearbox reaches 94% ~ 96%; three-stage stepper motor planetary gearbox 91% ~ 94%.

    3, the transmission power range is large: can be from less than 1KW to 1300KW, or even larger.

    4, the transmission range is large: i = 2.8 ~ 2000

    5, adaptability and durability. The main parts are made of high-quality alloy steel by carburizing and quenching or nitriding. The stepper motor planetary gearbox runs smoothly, with low noise and is used for more than 10 times.

    6, use and applicable conditions

Stepper motor planetary gearbox

The stepper motor planetary gearbox  has three horizontal series (NGW11-NGW121) and two levels (NGW42-NGW122) three (NGW73-NGW123). It is mainly used in metallurgy, mining, lifting and transportation machinery and equipment, and can also be used for power transmission under other similar industrial and mining conditions.

 Stepper motor planetary gearbox Stepper motor planetary gearbox

Servo planetary gearbox rated input speed up to 18000 RPM (about stepper motor planetary gearbox itself size, the greater the stepper motor planetary gearbox , the smaller the rated input speed) above, industrial-grade servo planetary gearbox output torque is generally not more than 2000 nm, special large torque servo planetary gearbox can do more than 10000 nm. Working temperature in 25 ℃ to 100 ℃ or so, by changing the grease can change its working temperature.

The operating temperature of the Servo planetary gearbox is generally from -25℃ to about 100℃. The maximum input speed can reach 18000rpm working life. The cumulative working time of the rated input speed is zbj19004-88 and zbj19026-90 noise ≤70 db


1 stepper motor planetary gearbox

2 installation method

3 important parameters

4 the concept

stepper motor planetary gearbox

Stepper motor planetary gearbox

The main transmission structure is: planet wheel, sun wheel, outer gear ring.Compared with other reduction gear, servo motor reduction gear has high rigidity, high precision (single stage can achieve less than 1 point),(double stage can achieve less than 3 points), high transmission efficiency (single stage in 95-99%), high torque/volume ratio, life maintenance free features.

Because of these characteristics, servo planetary gearbox is mostly installed in the stepper motor and servo motor or brushless motor, used to reduce the speed, improve the torque, matching inertia.

Rated input speed of servo planetary gearbox can reach up to 18000rpm(related to the size of the stepper motor planetary gearbox itself, the larger the stepper motor planetary gearbox , the smaller the rated input speed) above, the output torque of industrial grade servo planetary gearbox generally does not exceed 2000Nm


Stepper motor planetary gearbox


Installation method

Correct installation, use and maintenance of stepper motor planetary gearbox is an important link to ensure the normal operation of mechanical equipment.Therefore, when installing the stepper motor planetary gearbox , please be sure to strictly follow the following installation and use of related matters, carefully assemble and use.

The first step is to confirm whether the motor and stepper motor planetary gearbox are in good condition before installation, and strictly check whether the size of each part connected with the motor and stepper motor planetary gearbox is matched. Here are the size and matching tolerance of the positioning boss, input shaft and stepper motor planetary gearbox groove of the motor.

Step 2: unscrew the screw on the outer dustproof hole of stepper motor planetary gearbox flange, adjust the clamping ring of PCS system to align the side hole with the dustproof hole, insert the inner hexagon to tighten.After that, remove the motor shaft keys.The third step is to connect the motor with the stepper motor planetary gearbox naturally.The concentricity of the output shaft of the stepper motor planetary gearbox and the input shaft of the motor must be consistent when connected, and the outer flange of the two must be parallel.If the concentricity is not consistent, the motor shaft will be broken or stepper motor planetary gearbox gear wear.In addition, in the installation, do not use hammer and other blows, prevent the axial force or radial force too much damage to the bearing or gear.

Stepper motor planetary gearbox

Stepper motor planetary gearbox

Be sure to tighten the mounting bolt before tightening the force bolt.Before installation, wipe away the anti-rust oil of motor input shaft, positioning boss and connecting part of stepper motor planetary gearbox with gasoline or zinc-sodium water.Its purpose is to ensure tight connection and flexibility of operation, and prevent unnecessary wear and tear.Before the motor and stepper motor planetary gearbox are connected, the motor shaft keyway should be perpendicular to the tightening bolt.To ensure a uniform force, first screw the installation bolts at any diagonal position, but do not screw tight, then screw the installation bolts at the other two diagonal positions, and finally screw the four installation bolts one by one.Finally, tighten the force bolt.All tightening bolts shall be fixed and checked by the torque plate hand according to the indicated torque data.

Correct installation between stepper motor planetary gearbox and mechanical equipment is the same as correct installation between stepper motor planetary gearbox and drive motor.The key is to ensure that the output shaft of the stepper motor planetary gearbox and the drive part of the shaft concentricity.

Important parameter

Deceleration ratio: ratio of input speed and output speed.

Series: number of sets of planetary gears.Generally the maximum can reach three, efficiency will be reduced.

Full load efficiency: transmission efficiency of stepper motor planetary gearbox under maximum load (output torque of fault stop).

Working life: the cumulative working time of the stepper motor planetary gearbox at rated load and rated input speed.

Rated torque: it is the torque that the rated life allows for long running time.When the output speed is 100 r/min, the life of the stepper motor planetary gearbox is the average life, beyond this value, the average life of the stepper motor planetary gearbox will be reduced.The stepper motor planetary gearbox fails when the output torque exceeds twice.

Noise: unit dB (A), this value is the input speed of 3000 r/min, no load, 1 m away from the stepper motor planetary gearbox measured value.

Stepper motor planetary gearbox

Series: the number of sets of planetary gears. Since one set of planetary gears cannot meet the requirements of a larger transmission ratio, sometimes two or three sets are needed to meet the requirements of supporting a larger transmission ratio. Due to the increase in the number of planetary gears, the length of the second or third stepper motor planetary gearbox will be increased and the efficiency will be decreased.

Return clearance: when the output end is fixed and the input end is rotated clockwise and counterclockwise to produce rated torque +-2% at the input end, there is a tiny angular displacement at the input end of the stepper motor planetary gearbox , which is the return clearance.

Servo motor is an engine that controls the mechanical components running in a servo system. It is an indirect speed change device of a supplementary motor.

Stepper motor planetary gearbox

Servo motor can control the speed, position accuracy is very accurate, voltage signal can be converted into torque and speed to drive the control object.The rotor speed of the servo motor is controlled by the input signal and can respond quickly. It is used as an executive element in the automatic control system and has the characteristics of small electromechanical time constant, high linearity and starting voltage, etc. The received electrical signal can be converted into the angular displacement or angular speed output of the motor shaft.Divided into dc and ac servo motors, its main characteristics are that, when the signal voltage is zero, there is no rotation phenomenon, speed with the increase of the torque and uniform decline.

The basic information

Chinese name

Servo motor

Foreign names

Servo motor

type  equipment

Use occasions

Automatic control system

Stepper motor planetary gearbox


1 working principle

2 development history

3 selection comparison

4 debugging method

5 performance comparison

6 selection calculation

7 braking mode

8 points for attention

9 comparison of characteristics

10 scope of use

11 main functions

12 advantages

Fold edit this section working principle

1. Servo mechanism is used to make the position, orientation,


Stepper motor planetary gearbox


An automatic control system in which the output controlled quantity, such as the state, can follow arbitrary changes in the input target (or a given value).Servo positioning by pulse, basically can understand it, servo motor to receive a pulse, will rotate one pulse of the corresponding point of view, so as to realize the displacement, because, the function of the servo motor itself has a pulse, so each rotation Angle of a servo motor, send out the corresponding number of pulses, in this way, and the servo motor to accept pulse forming the echo, or closed loop, as a result, the system will know how many pulses sent to the servo motor, how much charge pulse back again at the same time, in this way, can be very precise control of the motor rotation, so as to realize accurate positioning, can reach 0.001 mm.Dc servo motor is divided into brush and brushless motor.Brush motor low cost, simple structure, large start torque, wide speed range, easy to control, need maintenance, but maintenance is not convenient (carbon brush), electromagnetic interference, environmental requirements.It can therefore be used in cost-sensitive general industrial and civil applications.

Stepper motor planetary gearbox Stepper motor planetary gearbox

Stepper motor planetary gearbox


Brushless motor small size, light weight, large output, fast response, high speed, small inertia, smooth rotation, stable torque.The control is complex, easy to realize intelligence, and the electronic commutation is flexible, which can be square wave commutation or sine wave commutation.Motor maintenance free, high efficiency, low operating temperature, small electromagnetic radiation, long life, can be used in a variety of environments.

2, ac servo motor is brushless motor, divided into synchronous and asynchronous motor, the current motion control is generally used synchronous motor, its power range is large, can do a lot of power.High inertia, low maximum rotational speed, and with the increase of power quickly decreases.Therefore, it is suitable for low speed and smooth operation.

3. The rotor inside the servo motor is a permanent magnet. The three-phase electricity controlled by the driver, U/V/W, forms an electromagnetic field.The accuracy of servo motor depends on the accuracy of encoder (line number).

The development history

Since the Indramat division of the Rexroth company of Germany MANNESMANN in 1978 Hanover trade fair


Stepper motor planetary gearbox

MAC permanent magnet ac servo motor and drive system were officially introduced in Shanghai, which marked that this new generation of ac servo technology has entered the practical stage.By the middle and late 1980s, companies had a complete range of products.The whole servo market has shifted to ac systems.Early simulation systems such as zero drift, anti-interference and reliability, accuracy and flexibility, as well as insufficient, is not fully meet the requirements of motion control, in recent years as the microprocessor, the application of new type digital signal processor (DSP), a digital control system, the control part can be fully carried out by software, called dc servo system, three-phase permanent magnet ac servo system.

Stepper motor planetary gearbox

Up to now, most of the high performance electrical servo systems adopt permanent magnet synchronous ac servo motors, while most of the control drivers adopt fast and accurate digital position servo systems.Typical manufacturers include Siemens of Germany, kohlmorgen of the United States and panasonic and yaskawa of Japan.

The small ac servo motor and driver are produced by yaskawa motor in Japan. Among them, D series is suitable for CNC machine tools (maximum speed is 1000r/min, torque is 0.25~ 2.8n.m), and R series is suitable for robots (maximum speed is 3000r/min, torque is 0.016~ 0.16n.m).After that, six series of M, F, S, H, C and G were introduced.The new D series and R series were introduced in the 1990s.From the old series of rectangular wave drive, 8051 MCU control to sinusoidal wave drive, 80C, 154CPU and gate array chip control, torque fluctuation from 24% to 7%, and improve the reliability.In this way, only a few years to form eight series (power range of 0.05~6kW) relatively complete system, to meet the working machinery, handling mechanism, welding robots, assembly robots, electronic components, processing machinery, printing press, high-speed winding machine, winding machine and other different needs.

Fanuc, a Japanese company known for producing CNC machine tools, also introduced s-series (13 specifications) and l-series (5 specifications) permanent magnet ac servo motors in the mid-1980s.The L series has a small moment of inertia and mechanical time constant, and is suitable for position servo systems that require special fast response.

Stepper motor planetary gearbox

Other Japanese manufacturers, such as mitsubishi motors (hc-kfs, hc-mfs, hc-sfs, hc-rfs and hc-ufs series), Toshiba seiki (SM series), okuma iron works (BL series), sanyo electric (BL series), and rishi electric (S series), have also entered the permanent magnet ac servo system competition.

The MAC series ac servo motors of Indramat division of Rexroth have 7 frame sizes and 92 specifications

The IFT5 series three-phase permanent magnet ac servo motors of Siemens are divided into standard type and short type

Stepper motor planetary gearbox

Ac servo motor and brushless dc servo motor in the function of the difference: ac servo is better, because it is sine wave control, torque ripple is small.Dc servo is a trapezoidal wave.But dc servo is simpler and cheaper.

The maximum speed of the high speed shaft does not exceed 1500r/min

     The peripheral speed of the gear does not exceed 10m/s;

     Working environment temperature is -40 ° C -45 ° C;

     It can be operated in both forward and reverse directions.

Stepper motor planetary gearbox

stepper motor planetary gearbox  specifications:

     NGW single-stage stepper motor planetary gearbox : NGW11, NGW21, NGW31, NGW41, NGW51, NGW61, NGW71, NGW81, NGW91, NGW101, NGW111, NGW121

     NGW two-stage stepper motor planetary gearbox : NGW42, NGW52, NGW62, NGW72, NGW82, NGW92, NGW102, NGW112, NGW122

     NGW three-stage stepper motor planetary gearbox : NGW73, NGW83, NGW93, NGW103, NGW113, NGW123

 Stepper motor planetary gearbox Stepper motor planetary gearbox

Stepper motor planetary gearbox

NGW stepper motor planetary gearbox specifications:

     The specifications of the stepper motor planetary gearbox  are divided into 12 frame numbers according to the transmission ratio, power and torque, and single-stage, double-stage and three-stage transmissions. There are 27 frame numbers and 58 speed ratios. The details are as follows:

stepper motor planetary gearbox are divided into single-stage, double-stage and three-stage transmissions: single-stage models are: NGW11 stepper motor planetary gearbox NGW21, NGW31, NGW41, NGW51 stepper motor planetary gearbox NGW61, NGW71, NGW81, NGW91 stepper motor planetary gearbox NGW101, NGW111, NGW121 ;

Stepper motor planetary gearbox

Debug method

1. Initialization parameters

Before wiring, initialize the parameters.

On the control card: select the control mode;Reset PID parameters to zero;Turn off the enable signal by default when the control card is powered on;Save this state to ensure that the control card is in this state when it is powered on again.

On the servo motor: set the control mode;Set to enable external control;Gear ratio of encoder signal output;Set the proportional relationship between the control signal and the motor speed.In general, it is recommended that the maximum design speed of the servo operation correspond to the control voltage of 9V.For example, yamyang sets the speed corresponding to 1V voltage and the factory value is 500. If you only want the motor to work below 1000 RPM, set this parameter to 111.

Stepper motor planetary gearbox

Stepper motor planetary gearbox

2, connection

Power off the control card and connect the signal line between the control card and the servo.The following lines must be connected: analog output line of control card, enable signal line, encoder signal line of servo output.The motor and the control card (as well as the PC) are powered up after the wiring is rechecked to be correct.At this point the motor should be stationary and can be easily turned by external forces. If not, check the setting and wiring of the enabling signal.Rotate the motor with external force, check whether the control card can correctly detect the change in the position of the motor, otherwise check the wiring and setting of the encoder signal

Stepper motor planetary gearbox

3. Try the direction

For a closed-loop control system, if the feedback signal is not in the right direction, the consequences must be disastrous.Enable signal to turn on servo via control card.This servo should rotate at a lower speed, which is the legendary "zero drift".There are instructions or parameters on the control card to suppress zero drift.Use this instruction or parameter to see if the speed and direction of the motor can be controlled by this instruction (parameter).If it cannot be controlled, check the analog wiring and the parameter setting of the control mode.Confirm to give a positive number, motor forward rotation, encoder count increase;Given a negative number, the motor turns back and the encoder count decreases.If the motor is loaded and the stroke is limited, do not use this method.Test do not give too much voltage, recommended under 1V.If the direction is inconsistent, the parameters on the control card or motor can be modified to make them consistent.

Stepper motor planetary gearbox

4. Inhibit zero drift

In the closed-loop control process, the existence of zero drift will have a certain influence on the control effect, and it is better to restrain it.Control card or servo control parameters to control zero drift, carefully adjusted so that the motor speed is close to zero.Because zero drift itself also has a certain degree of randomness, so it is not necessary to require the motor speed is absolutely zero.

5. Establish closed-loop control

Once again, the servo signal is released through the control card, and a small proportional gain is input on the control card. As for how small the gain is, it can only be determined by feeling. If you are really not assured, enter the minimum value allowed by the control card.Turn on the enable signal of the control card and the servo.At this point, the motor should be able to roughly follow the motion instructions.

Stepper motor planetary gearbox

6. Adjust the closed-loop parameters

Fine-tuning the control parameters to ensure that the motor moves according to the instructions of the control card is a must, and this part of the work, more experience, here can only be omitted.

Fold edit this section performance comparison

Performance comparison between servo motor and stepping motor

Stepper motor planetary gearbox

As an open-loop control system, stepper motor has an essential relationship with modern digital control technology.Stepping motor is widely used in the digital control system in China.With the appearance of all-digital ac servo system, ac servo motor is more and more applied in digital control system.In order to adapt to the development trend of digital control, stepper motor or full digital ac servo motor is used as executive motor in motion control system.Although the two are similar in control mode (pulse train and direction signal), there are significant differences in performance and application.Make a comparison with respect to the service performance of both now.

Stepper motor planetary gearbox

The transmission ratio is: 2.0, 3.15, 3.55, 4, 4.5, 5, 5.6, 6.3, 7, 1.8, 9, 10, 11.2, 12.5;

Two-stage models are: NGW42, NGW52, NGW62, NGW72, NGW82, NGW92, NGW102, NGW112, NGW122;

The transmission ratio is: 14, 16, 18, 20, 22.4, 25, 28, 31.5, 35.5, 40, 45.50, 56, 63, 71, 80, 90, 100, 112, 125, 140, 160;

Stepper motor planetary gearbox

The three-level models are: NGW73, NGW83, NGW93, NGW103 gear stepper motor planetary gearbox NGW113, NGW123 stepper motor planetary gearbox ;

The transmission ratio is: 180, 200, 224, 250, 280, 315, 355, 400



07 September 2019


Planetary Gear Motors

 sogears manufacturing

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