EWA14 Series Slewing Drive

A slewing drive is a gearbox that handles radial or axial loads with high rotational torque. In addition, the slewing ring bearing at the heart of the drive enables it to withstand high cantilever or moment loads. A descendant of the "worm" lead screw, slewing drives are found in construction machinery, manufacturing, military equipment, and many other applications where strength and precision are required.

The physics of slewing drives make them a versatile solution for many applications. In operation, the axial motion of the slewing drive or motion about its axis interacts to generate radial torque. This action occurs by meshing the grooves of the horizontal screw with the teeth of the vertical gear. When turning, the axial movement of the worm gear transfers the amplified torque force to the radial gears. The number of threads on the horizontal screw and the number of interacting gears will determine the speed ratio of the unit.

Slew Drive Specifications

Depending on the configuration of the slew drive and the purpose of the equipment, each unit will have differing specifications. When defining the type and capability of the slew drive, the following variables are calculated:

• Gear ratios
• Precision
• Weight
• Output
• Tilting moment
• Torque
• Dynamic and static axial
• Radial dynamic

Performance Parameters

Front View	Top View

How Do Slew Drives Work?

The mechanics behind it is built on the concept of a worm wheel where a slewing ring with external teeth is meshed with complementing worm gear with a predefined gear ratio. Internal components are contained and assembled inside a cast iron or aluminum housing for protection and installation.

The unique design of a slew drive allows it to utilize two perpendicular planes transmitting high output rotational torque with a relative speed ratio to its inputs. As the worm gear rotates through a low input torque on the horizontal plane, its hardened teeth translate rotational motion onto the external slewing teeth. This force creates a rotation around the perpendicular axis of the slew drive through the slewing outer ring.

A worm-wheel design allows a wide range of low torque inputs to the slew drive to transmit or hold high torque applications. Slew drives can be found across several constructions and heavy machinery equipment. The versatility and weight allow slew drives to act as an immediate solution to rotary-related issues.

Slewing Drive Features

Slewing drives are unique in the market because of their versatility. While a slewing drive comes standard in size and outer dimensions, customization and customer-specific requirements can be adhered to in the early design phases. The worm gear input can be modified to fit different motor input shaft dimensions per application requirements. Cast iron or aluminum end caps are bolted down on both sides of the worm shaft to press the gear into position. This prevents axial play and provides better control over backlash.

The standard orientation of a slew drive is horizontal, allowing high axial loads and minimal radial loads. However, the vertical direction is widely spread across different applications. The number of bolts and their distribution on the slewing drive surface plays a significant role in the load capacity of a slew drive but can be custom modified to fit/replace current models used by our customers.

Other slew drive features include:

• Maximum load capacity.
• Compact design to save space.
• Simple integration into existing applications.
• Quick customization options.

Applications of Slew Drive

There are limitless possibilities where slew drives can be used and also improve the usability of existing equipment to a whole new level. To give you an idea of what kind of industries they're used to daily. Here are some of the applications.

Custom Slewing Drives

HZPT provides its customers with a high-quality application-based slew drives product line. Sizes range from 7.5" (200mm) up to 20" (500mm) in ID. Standard hydraulic or electric motors rotate the drive-through standard worm shaft inputs and can be assembled upon customer request, depending on their application.

Our engineers are well equipped with the tools and technology necessary to work alongside our customers. We work to understand their applications, design requirements, project scope, and loads and help identify the most suitable products. We are ready to provide technical support and slew drive recommendations based on application requirements.

For over three decades, slewing rings and slew drives have proven their worth in the most varied application areas. We've been supplying products to many of our customers for decades. We'd love to have the opportunity to win you over with our technological competence, too!