Not everyone knows what a planetary gearmotor is and how important it is for industry. This mechanical device combines an electric motor and a planetary gearbox, i.e. a gear-based speed reduction device. The planetary gearmotor is used to change the speed and torque ratios between the input and output shafts. It is a device that has so many applications. We will look at some of these later.
How a planetary gearmotor is made up.
To understand what a planetary gearmotor is, let us begin by analysing its structure. Typically, the gearmotor consists of a cylindrical steel body, with an internal spur gear obtained by broaching, ball bearings and an upper and lower flange. Inside the body are gears or satellites positioned on a satellite holder inside the internally toothed crown gear. The gears rotate around a sun gear in the centre of the satellite holder. The transmission of motion is via the motor shaft, at the input. The gear shaft, on the output side, transmits the torque. The gearmotors shafts can have different diameters depending on the individual application.
This set-up allows for high reduction ratios, high torques, through gears that reduce the forces on the gear teeth, all within the compactness and versatility of use.
It is possible to have several stages/reduction stages depending on the reduction ratio and the performance you want to achieve. he number of stages varies from 1 to more than 6, considering that a higher number of stages results in a higher reduction ratio. A reduced number of stages, on the other hand, results in reduced torque and higher speed. So, to summarise, the number of stages determines the output torque, reduction ratio, reduction speed and overall size.
Reversibility
Finally, planetary gearmotors can be reversible, allowing the direction of rotation to be reversed between the motor and gearbox shafts.
This can be achieved by the presence of the 3 types of gears, the sun pinion, the planetary satellites and the crown wheel. The direction of rotation can, in fact, be reversed by stopping the planet gears. All planetary gearboxes in the Automec series always guarantee static reversibility, regardless of the type of motor coupled.
What are the advantages of a planetary gearmotor.
Having analysed what a gearmotor is, let us now look at the specific advantages of a planetary gearmotor. The design of these devices offers numerous benefits, let us see here some of the main ones.
- Compact design: the advantages of planetary gearmotors are many. They are compact gearmotors while still being able to achieve high reduction ratios. They are also easy to install, require no special maintenance and are long-lasting.
- Lubrication retention: they are lubricated for life thanks to the possibility of recovering the oil removed from the sun gear. This also ensures that lubrication is not lost even at higher speeds, unlike spur gears that tend to drain oil.
- Load distribution: Planetary gearmotors are highly efficient, distributing the torsional load over several planetary gears. This allows higher torque loads to be handled without the wear and stress of individual gears.
- Load sharing: Due to the presence of several planetary gears, the load is shared between them in the various reduction planes. This allows for improved efficiency and reduced noise.
Where planetary gearmotors are used.
Precision applications: how multistage planetary gearmotors improve overall performance.
Research results indicate that multistage planetary gearmotors improve overall performance compared to single-stage gearmotors:
- Higher reduction ratios: the presence of multiple stages of planetary gears allows multi-stage designs to achieve truly significant reduction ratios. Reduction ratios exceeding 100:1 or even 300:1 can be achieved. This allows high input speeds to be translated into very low and precisely controlled output speeds.
- Increased torque capacity: the additional gear stages of multistage planetary gearmotors allow them to handle significantly higher torque loads than single-stage versions. This makes them suitable for applications requiring both high torque and slow, precise movement.
- Improved efficiency: while an extra gear stage may reduce efficiency slightly, multi-stage planetary gearboxes are able to optimise the internal power transmission and minimise losses in each stage, resulting in a cumulative efficiency often exceeding 90%.
- Increased precision: the multi-stage planetary configuration helps to dampen the effects of fluctuations in the individual gears, minimising speed/torque variations at the output and thus ensuring optimum precision in movement.
- Compact dimensions: intelligent design allows multistage planetary gearmotors to be built in incredibly small and lightweight packages, saving space and weight compared to other gearmotors.
Main areas of use for planetary gearmotors
- Automation: planetary gearmotors are widely used in automation, especially for printing, packaging, food sector, agrarian sector and general handling.
- Robotics: planetary gearmotors are commonly used in robotic arms and couplings due to their compact design, high torque density and efficient power transmission.
- Industrial machinery: planetary gearmotors are used in a variety of industrial equipment such as conveyors, stabilizers, labelling machines, reamers, excavators, bottle washer, pizza ovens, mixers and pumps, providing high torque capacity for heavy-duty applications.
In summary, the main applications exploit the key advantages of planetary gearmotors – high torque density, compact size, high efficiency and precise motion control – in a wide range of sectors, including automotive, labelling and printing, food sector, agrarian sector, robotics, aerospace, industrial, renewable energy, medical and defence.
We hope with this short article to have helped you understand what a planetary gearmotor is and what its importance is within the machines of modern technology. We know we cannot have been 100% exhaustive, if you have any questions please do not hesitate to contact us.
