With the many commercial gearboxes on the market, it’s important to match the proper kind of gearbox with the drive, motor, and load. When a machine needs a servosystem (drive and electric motor), the gearbox type is crucial for accurate and repeatable movement. Planetary gearboxes fit the bill for servo applications.
High-precision helical planetary gearboxes are an excellent choice for applications that require accuracy and reliability. Planetary gearboxes possess very low backlash ratings (typically ranging from one to nine arc-min), so when sized correctly offer a service existence of over 20,000 hours with practically no maintenance. Helical planetary gears provide very calm and more efficient operation in comparison with competitive products.
Precision gearboxes are carefully machined to high tolerances – believe clockmaker, not blacksmith. They provide power densities that translates to small bundle size and efficiencies of 90% and greater.
Servomotors often drive loads directly without the need for a gearbox, however in many applications it’s beneficial to make use of a gearbox between the motor and load.
One main reason to use a gearbox is torque multiplication. It lets designers make use of smaller sized servosystems that consumes less energy. Instead of buying relatively huge servodrives and motors, designer can use smaller components, saving space and money.
Output torque increases in direct proportion to the gear ratio, and top acceleration of the output shaft decreases. If an application can withstand the reduced speed, a relatively little servosystem can supply high torque.
Gearboxes may also address inertia mismatches. For high performance servosystems — those with high dynamic responses or low overshoot, for instance – the ratio between the reflected load inertia and motor inertia should be as low as practical, ideally under ten-to-one. A precision gearbox decreases the reflected inertia by the square of the decrease ratio. For instance, using a 25:1 gearbox decreases the load’s reflected inertia by one factor of 625, a significant improvement.