Planetary Ring Gear

Precision Pinion Internal Ring Gear for Planetary Gear



The planetary gear is a gear transmission in which at least one gear has a collective shaft that rotates around the central shaft. The outermost ring of this transmission is called the ring gear. The internal gear is on the same axis as the planet carrier in the planetary gear transmission. The inner ring gear is used in a considerable amount. The inner teeth are usually formed by inserting teeth, pushing teeth, and pulling teeth, which are difficult to process and have low material utilization. The obtained internal ring gear has low hardness. The general internal ring gear processing method has a long production process. Material and product energy consumption are relatively high, resulting in increased costs.


Model Number M3,M4,M5,M8,M12 and etc.
Material Brass, C45 steel, Stainless steel, Copper, POM, Aluminum, Alloy, and so on
Surface treatment Zinc-plated, Nickel plated, Passivation, Oxidation, Anodization,
Geomet, Dacromet, Black Oxide, Phosphatizing, Powder Coating, and Electrophoresis
Standard ISO, DIN, ANSI, JIS, BS, and Non-standard.
Precision DIN6,DIN7,DIN8,DIN9.
Teeth treatment Hardened, Milled, or Ground
Tolerance 0.001mm-0.01mm-0.1mm
Finish shot/sandblast, heat treatment, annealing, tempering, polishing, anodizing, zinc-plated
Items packing Plastic bag+Cartons Or Wooden Packing
Payment terms T/T, L/C
Production lead time 20  business days for sample,25 days for the bulk
Samples Sample price range from $2 to $100.
sample express request paid by clients
Application 1. Automatic controlling machine
2. Semi-conductor industry
3. General industry machinery
4. Medical equipment
5. Solar energy equipment
6. Machine tool
7. Parking system
8. High-speed rail and aviation transportation equipment, etc.


Advantages of planetary gear transmission

1. Compact structure, small size, and lightweight

The planetary transmission has the characteristics of planetary motion and power split. It only has the internal gear pair, which can make full use of the large bearing capacity of the inner tooth and the entire space of the internal gear ring, so that the device has the advantages of compact structure, small outline size, lightweight, etc. generally, when the transmission power and transmission ratio are the same, the volume and weight of the planetary gear reduction motor is about 1/2 to 1/6 of the standard gear transmission.


2. The large transmission ratio can realize the synthesis and decomposition of motion

There are many types of planetary transmissions, such as involute planetary transmissions, cycloidal pinion, harmonic planetary transmissions, and movable-tooth planetary transmissions, which are generally characterized by large transmission ratios. When used for transmitting motion, its maximum transmission ratio can reach tens of thousands or hundreds of thousands. Its maximum transmission ratio can get tens or hundreds as power transmission. The planetary message of the differential motor can realize the combination of two motions and the decomposition of one action. In some cases, the type of planetary gear motor can be appropriately selected to learn the complex movements with various speeds.

3. High efficiency and low power loss

The planetary transmission adopts several planetary wheels evenly distributed between the inner and outer center wheels, which can balance the inertia force acting on the center wheel and the planet carrier bearings. Using this symmetrical structure is beneficial to improving the efficiency of the transmission system. Appropriate selection of the transmission type is best to select a good design to make the efficiency of the planetary gear reduction motor reach 0.97 ~ 0.99.

4. Balanced transmission, strong shock, and vibration resistance

The use of several planetary gears is distributed between the two center wheels. The load-sharing device maintains the uniform load distribution and power evenly distributed between the planetary gears. Not only can it balance the inertia force of the planetary gears and the rotating arm but also significantly improve the stability of the planetary geared motor and the ability to resist impact and vibration.

The direction of development. Planetary transmission technology has become an essential development direction of mechanical transmission technology in various countries globally. It is mainly reflected in the wide use of hard tooth surfaces, high precision, high speed, high power, ample torque, and large specifications. Planetary geared motors have been widely used as deceleration, speed-up, differential, speed-change, or control devices.

The inner ring gear is characterized by small size, lightweight, wide speed ratio range, high transmission efficiency, and low noise. It is a transmission device for the speed increase, reduction, and change. The primary forms are involute planetary transmission, planetary transmission with few teeth differences. Commonly used processing methods are: milling, hobbing, honing, shaping, honing, combing, squeezing, grinding, grinding, and scraping. Due to the different types of gears, manufacturing methods, and inspection methods, parts should be inspected individually according to requirements in small batch production. In mass production, daily testing is generally used instead of single testing to increase productivity and ensure quality and reduce costs. Meanwhile, regular inspection is also required for process equipment, machine tools, and measuring tools.


The commonly used methods for tooth thickness detection: are the tooth thickness vernier caliper measurement method, ball cargo roller measurement method, and expected standard length measurement method. The typical average micrometer measurement is simple, accurate, practical, and does not accept the limitations of the measurement reference. The length refers to the tolerance of the outer diameter of the gear. The standard regular micrometer or ordinary vernier caliper can be used, suitable for various production methods and internal and external teeth.

The roughness of the tooth surface is checked by the comparison method; that is, the standard block is compared with the measured tooth surface and evaluated by eye and registration. Our company adopts a roughness measuring instrument to check.

The critical problem of gear shaping for internal gears with large and medium modules is reducing the roughness of the tooth surface. To this end, the following measures are often taken:

1) Improve the cutting performance of the material to facilitate cutting.

2) Increase the rigidity of the shaper mold and reduce the vibration during processing.

3) After gear shaping, add shaving or honing technology.

The main factors causing errors in the ring gear are:

Theoretical error: the error caused by the defect in the principle of the processing equipment, which cannot be wholly overcome due to conditions. For example, the involute tooth profile is theoretically a smooth continuous curve. In manufacturing, hi cannot reach absolute smoothness because the hob tooth profile is linear.

Machine error: the geometric accuracy error of the machine tool causes errors in gear geometry and size.

Tool error: manufacturing and installation errors of the tool.

Fixture error: the error of the fixture during the manufacturing, installation, and use.

Measuring Error

Deformation error: deformation and vibration of the workpiece caused by cutting force, cutting heat, internal stress, etc., during the cutting process, improper clamping of the workpiece, heat treatment deformation, and workpiece heating will cause deformation errors of the workpiece.

Operation error: improper adjustment of the machine tool, improper workpiece installation, unsuitable selection of operating procedures, and cutting quantity.