Structural Principle of Planetary Gearbox

- Apr 03, 2019-

First, the planetary reducer components: 

Body, output shaft, output shaft oil seal, output bearing, sun nut, planet carrier, internal gear ring, planetary gear, stage gear, needle roller shaft, sun gear, C-shaped buckle, input force Bearings, input shaft oil seals, input flanges, O-rings, vent plugs, keys, washers, hexagon socket screws, etc.

Second, the planetary reducer transmission principle: 

The planetary reducer transmission structure is the highest efficiency of the current gear reducer, the basic transmission structure is four parts:

      1, the sun gear

      2, planetary gear (combined in the planet carrier)

      3, the internal gear ring

      4, stage gear

The drive source activates the sun gear in a direct connection, and the sun gear drives the planetary gears combined on the planet carrier. The entire planetary gear system rotates automatically along the outer gear ring, and the output of the planetary frame is connected to the output shaft for acceleration. Higher reduction ratios need to be multiplied by multiple sets of stage gears and planetary gears.

G+ Planetary Gearbox

Third, the planetary reducer deceleration characteristics:

1. High torque and impact resistance: The mechanism of the planetary gear is the same as the transmission mode of the traditional parallel gear. The conventional gear only relies on a very small number of contact surfaces between the two gears to drive, and all the load is concentrated on a few gear faces that are in contact with each other, which easily causes friction and breakage between the gears. The planetary gear reducer has a 360-degree uniform load on the 360-degree contact surface of the gear, and the multiple gear faces are evenly subjected to the instantaneous impact load, so that it can withstand the impact of higher torque, and the body and the bearing parts are not. It will be damaged and broken due to high load.

 2, small size, light weight: the design of the traditional gear reducer has multiple sets of large and small gears offset to the staggered drive deceleration, because the reduction ratio must be generated by the multiple of the number of two gears, the size of the gears must have a certain distance between the bite, Therefore, the tooth box accommodating space is extremely large, especially when the combination of the high speed ratio is more required to be combined by more than two reduction gear boxes, the structural strength is relatively weakened, and the length of the tooth box is lengthened, resulting in a huge volume and weight. The structure of the planetary reducer can be repeatedly connected according to the number of segments required, and the multi-section combination can be completed separately, and the volume is small, the weight is light, the appearance is light, and the shape makes the design more valuable.

3. High efficiency and low backlash: Since each gear of the gear reducer has only one tooth face engagement when it is decelerating, it needs more tooth surface stress when the gear is equal to the torque. Therefore, the gear design must adopt a larger die. The number and thickness, the larger the gear modulus, the greater the deflection tolerance between the gears, and the higher the gear gap, the cumulative backlash between the reduction ratios of each segment increases. The unique multi-point of the planetary gear combination is evenly sealed, and the arc-enclosed structure of the outer gear ring makes the outer gear ring and the planetary gear tightly combined, and the tightness between the gears is high, in addition to the extremely high speed reducer efficiency. The design itself achieves high-precision positioning.

Planetary Gearbox with Motor

Fourth, the planetary reducer installation method:

In the family of reducers, planetary reducers are widely used in servo, stepping, DC and other transmission systems due to their small size, high transmission efficiency, wide deceleration range and high precision. Its role is to reduce the speed increase torque and reduce the load/motor moment of inertia ratio under the premise of ensuring precision transmission. Proper installation, use and maintenance of the reducer is an important part of ensuring the normal operation of mechanical equipment. Therefore, when installing the planetary reducer, be sure to carefully assemble and use it in strict accordance with the following installation and use.


1. Before installation, confirm whether the motor and reducer are intact, and strictly check whether the dimensions of the parts connected to the reducer are matched. Here are the dimensions and matching tolerances of the positioning boss, input shaft and reducer groove of the motor.

2. Unscrew the screw on the outer dust-proof hole of the reducer flange, adjust the clamping ring of the PCS system so that the side holes are aligned with the dust-proof holes, and insert the inner hexagon to tighten. After that, remove the motor shaft key.

 3. Connect the motor to the reducer naturally. When connecting, it must be ensured that the output shaft of the reducer is concentric with the input shaft of the motor, and the outer flanges of the two are parallel. As the heart is inconsistent, it will cause the motor shaft to break or the reducer gear to wear.

GPB Planetary Reducer

As a professional speed reducer manufacturer, Saini Intelligent is specialized in producing planetary gearhead reducer for more than 10 years. All of G+ planetary gearboxes are designed with integral structure with large span of the front and rear bearings distributed inside the box body, forming a stable integrated structure to ensure transferring the largest torque in the most compact form.

Welcome to order Planetary Gearbox from Saini Intelligent.

Right Angle Planetary Gearbox