Slewing Drives: Single Worm & Double Worm Drives

Slewing drive

The slewing drive is a gearbox that can safely hold radial and axial loads, as well as transmit a torque for rotating. The rotation can be in a single axis, or in multiple axes together. Slewing drives are made by manufacturing gearing, bearings, seals, housing, motor and other auxiliary components and assembling them into a finished gearbox.

History

The slewing drive is a modernized take on the worm drive mechanism that dates back many centuries and was widely used during the Renaissance Era. Pappus of Alexandria (3rd century AD), a Greek mathematician is credited for an early version of the endless screw, which would later evolve into the worm drive. This mechanism was also used by Leonardo da Vinci as a component in many of his designs for machines. It can also be found in the notebooks of Francesco di Giorgio of Siena. Many slewing drive concepts found prominence with the emergence of larger scale construction and engineering in the height of the Greek and Roman Empires.

Technology

Slewing drives function with standard worm technology, in which the worm on the horizontal shaft acts as the driver for the gear. The rotation of the horizontal screw turns a gear about an axis perpendicular to the screw axis. This combination reduces the speed of the driven member and also multiplies its torque; increasing it proportionally as the speed decreases. The speed ratio of shafts depends upon the relation of the number of threads on the worm to the number of teeth in the worm wheel or gear.

As technology has improved, more slewing drives are using hourglass worm technology, in which the worm is shaped to engage more teeth in the gear. This increased tooth engagement results in greater strength, efficiency and durability.

Performance characteristics

Because of their multiple uses, slewing drives come in a variety of model sizes, performance ranges and mounting characteristics. The drives are well suited for applications that require both load holding and rotational torque from the same gear box. They can also be made with dual axes of rotation, (turning axes at the same time) or with dual drives on the same axis, (two worm threads driving the same ring gear in one axis).

Materials

The specifications for drives and gears varies depending on the material the gear is composed of However, a majority of the drives and gears commonly used are composed of steel and phosphor bronze. According to an extensive series of tests by the Hamilton Gear & Machine Co., chill-cast nickel-phosphor bronze ranked first in resistance to wear and deformation. Number two on the list was SAE No. 65 bronze. For bronze gears a good casting should have the following minimum physical characteristics:

Single Worm slewing drive

Applications

SE Enclosed Slew Drives help power movement across industries and are perfect for situations requiring both load-holding and rotational torque from the same gearbox. Typical applications include solar trackers, wind turbines, satellite and radar dishes, truck cranes, man lifts, utility equipment, hydraulic equipment attachments, oil tool equipment, tire handlers, digger derricks, and automotive lifts.

Specifications

Our base model sizes deliver performance ranges from 6kNm to 220kNm of holding torque, 200Nm to 63kNm of output torque, 500Nm to 271kNm of overturning moment load capacity, and gearbox reduction ratios of 30:1 up to 156,600:1. The mounting can be done horizontally, vertically, or across a combination of multiple axes. Get detailed specifications.

Reliability

Our SE drives offer an IP55-rated enclosure that demonstrates nearly complete protection from environmental particles such as dust, dirt, sand, and even water. Our testing equipment and procedures allow us to provide a 30-year performance guarantee, making Xuzhou Wanda Slewing Bearing the smartest and most reliable slew drives available.

Xuzhou Wanda Slewing Bearing methods and procedures earned ISO 9001, CE, REACH, and TUV certifications. We qualify all the raw materials, components, and final assemblies in our own facility to meet these standards.

Performance

Our slew drives are powered with patented hourglass worm technology to give increased efficiency and accuracy. Unlike standard worms which touch only one tooth, our hourglass worm engages 5 to 11 teeth on the pitch line of the ring gear from the hourglass thread. This increased tooth engagement gives the gearbox enormous strength and power. See how the hourglass worm improves performance.

Double worm slewing drive

Applications

The most common slewing drive application for the dual-axis slewing drives are dual-axis solar trackers, such as heliostats and concentrated photovoltaics (CPV), and satellite or radar dishes. Other applications include automotive lifts, robotic arm positioners, and stage equipment.

Specifications

Our base model sizes deliver performance ranges from 3,000Nm to 10,000Nm of holding torque, 200Nm to 3,700Nm of output torque, 500Nm to 13,000 Nm of tilting torque, and gearbox reduction ratios of 30:1 up to 156,600:1 on each axis. The drives can be mounted horizontally, vertically, or on a combination of multiple axes. Get more information.

Reliability

Xuzhou Wanda Slewing Bearing SDE dual-axis slewing drives are guaranteed for a 30-year field life of precise 3D positioning. SDE drives create an efficient and reliable solution in a single drive. We qualify all of our components and raw materials using standards set by ISO 9001, CE, REACH, and TUV certifications to maximize field life.

Performance

Xuzhou Wanda Slewing Bearing slew drives use patented hourglass worm technology to give maximum control and movement support. Our worm gears engage 5 to 11 teeth on the pitch line of the ring gear from the hourglass screw, which is higher tooth engagement than standard worms, giving the gearbox greater stability and strength. Learn more about hourglass technology.