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Mode of operation

Planetary gears (PLG's) work as the name implies: the sun wheel is in the center and driven by the motor. It confers its motion onto three rotary planetary wheels which form a stage. They are arranged on the bearing bolt of a planetary carrier. The last planetary carrier in each case is rigidly connected to the drive shaft and so provides power transmission. On the outside the planetary gear wheels also rotate in a gearbox with internal gearing, the so-called hollow wheel.


Input and output are arranged coaxially. The shafts rotate in the same direction. PLG's are suitable for clockwise and counter-clockwise rotation, alternating operation, continuous and intermittent operation and are characterized by a high level of efficiency. The compact design offers high power density compared to other gear designs and high torque transmission for extremely small installation space.

Driving torque

Output torque is the most important parameter when choosing a planetary gear head. Gear reduction reduces the relatively high rotational speed of the motor (rpm), delivering a lower rotational speed at the output end. This increases the output torque in an inverse ratio.

Connecting flange

This is where the flexibility of the PLG manu­facturers comes into its own. All IMS Gear planetary gear heads can be adapted to fit all (!) motors. Individual solutions are possible at the input and output ends.

Load on output

As different manufacturers use different measuring methods, great care must be ­taken when seeking to make a comparison. We would be pleased to calculate the maximum axial and radial load for your specific application under consideration of all parameters. Higher loads can be achieved through design measures.
Please contact us: Contact partner

Operational dynamics

High levels of operational dynamics, achieved through low inertia torques, smooth running and low levels of mecha­nical wear. IMS Gear Planetary Gears uses plastic instead of metal for its planetary gears wherever appropriate and technically feasible. This delivers low inertia torques. Smooth running is something we achieve when required through the use of high-quality needle bearings, or through the low friction coefficients achievable between plastic and metal. We achieve low levels of mecha­nical wear through our specialist design of gearing and through the use of plastic gears. The material mix characteristics of IMS Gear assures superlative operational dynamics.
Also refer to ball bearings

Operating factor cB

The mentioned operating factor  cB = 1,0 does refer to a constant direction of rotation, no shock load and a daily operating time of 3 hours.

Operating temperature

The operating temperature depends on the material and lubrication. Our pure metal versions with standard lubrication range between −30° and +120° C, the PK-series made of plastic between −15° und +65° C.

Sealing measures

The types of protection are defined in acc. with DIN EN 60529. IMS.baseline gear drives fullfill the following protection categories:
Gear drives with sintered bearings: IP40
Gear drives with ball bearings (2RS): IP53
Upon request you can obtain output and motor gaskets that enable you to leverage higher protection classes.

Installation position

Due to grease lubrication the plane­tary gear drives of IMS Gear can be installed in any desired position. In vertically arranged outputs, additional sealing measures can be provided upon ­request.

Gear backlash

Gear backlash depends on a large number of factors: Type of load, number of gear ratios, bearing, version or combination of materials. When seeking to compare different manufacturers, always remember that here, too, there are no standardized measuring methods.

Ball bearings

In standard versions, the outer race of the ball bearing is designed as a rigid interference fit, while the inner race on the output shaft is designed as a loose interference fit (i.e. one capable of rotation). If required, other designs can also be provided.

Service life

Depending on environmental conditions and the operating data of the drive system, the service life of a PLG ranges between 200 and 15,000 hours. The great variety of application options precludes any generally applicable forecast of service life.

Scope of delivery

IMS Gear Planetary Gears can supply you with gears completely assembled and tested with any motor of your choice, or singly with a motor pinion for self-assembly.


Our PLG’s are lubricated with grease and therefore maintenance-free during their ­service life. Depending on requirements profile, we select the optimum lubricant from more than ten options.

Low-noise transmissions

To obtain optimum acoustic performance, increased demands on concentricity and ­axial run-out of the motor end plate, flange and shaft need to be met. Axial forces act on the motor shaft due to helical gearing. Sufficient dimensioning of the motor shaft bearings should be taken into account here. To counteract the grease-promoting effect of helical gears, radial shaft sealing rings or sealed motor bearings can be used.

Overload torque

Maximum overload torque (impact loading) is the short-term overloading of the permitted output torque, i.e. when starting the motor. In case of plastic PLG’s the peak load equals the overload. In case of metal-plastic combinations or full metal versions the overload torque can even amount to 1.5 times the peak load.

Gear reductions

By changing the number of teeth of the sun wheel and the planetary wheels, a number of reductions are possible in one stage. IMS Gear Planetary Gears combines reduction ratios in up to four gear stages. This allows the realization of a huge variety of different gear specifications.

Heat treatment

Structural conversion during hardening of the individual metal parts acts positively on the strength and wear behavior of the gears. IMS Gear has its own heat treatment shop. As the entire metal manufacturing is inhouse, we can choose from various steels for hardening.


The gear efficiency rating only takes account of the rolling motion of the gear, whereas the gear head efficiency rating takes account of all the losses of the entire bearing. We also always quote the transmission effi­ciency rating at this point. By necessity this is lower than the gear efficiency rating. As there are no standardized measuring methods, a comparison of efficiency levels of different manufacturers always requires special attention. In case of any specific requirements, please talk to us.

All figures are approximate values. Variations are possible and may arise for example due to non-standardized inspection and measurement methods. For more detailed information, please contact us directly. The company always reserves the right to make technical modifications.