Why cycloidal rotary indexers are the better choice
The rotary indexers of our RS series are based on time-proven cycloidal gear technology that has been in use for decades in robotics; they feature high positioning accuracy and outstanding performance in a compact form. Their special design makes them much more precise, dynamic and rigid than conventional solutions – which enables faster machining times, better product quality and maximum efficiency.
Rotary indexers (also known as rotary tables, indexing tables or spinning tables) carry out rotational motions. They enable short switching and cycle times in virtually every industry – from automotive to machine and plant engineering, from battery production for electric cars to machine tool construction and food production. They move components and workpieces into position and provide for transport from one machining station to the next. Rotary indexers are often integrated as components in positioners, but are also used separately (e.g. in applications requiring a swivel axis).
Applications for rotary indexers:
- Positioning
- Handling
- Feeding
- Assembly
- Transport
Rotary indexers: The difference is in the drive technology
Conventional rotary indexers are normally equipped with worm, cam or direct drives. But all of these technologies have their weaknesses, which lead to compromises in performance, durability, size, and/or flexibility. As a result of their design, worm gear drives are very inefficient and show signs of wear after a while. As self-locking gears, their friction has a negative effect on dynamics. Cam-driven rotary indexers generally have fixed cam profiles, which makes them very inflexible. Direct drives are expensive, difficult to mount and have high requirements for resources such as electrical power. They also require an additional cooling system (usually water cooling).
Rotary indexers based on cycloidal gear technology eliminate such problems. Their special design makes them much more precise, dynamic and rigid than conventional solutions – which boosts performance and reduces your costs.
Cycloidal gears are an innovative alternative for servo controlled rotary indexers
Cycloidal gears feature high gear reduction rates, outstanding shock resistance (up to 500 % of the rated torque), and minimal backlash throughout the entire life cycle (hysteresis loss < 1 arcmin, purely mechanical backlash 0.1 – 0.2 arcmin) – which makes them an efficient alternative for rotatory positioning applications. Exact and dynamic positioning allows fast movement to processing or loading and unloading stations with accuracy in the arcsecond range. This reduces process times and error ratios. And there are no limitations with respect to the position: Any point within 360° can be reached. In addition, cycloidal rotary indexers can be operated by the robot controller as an external axis, which allows cycle-time concurrent processes.
Advantages of cycloidal gears in turning applications:
- Pin-point motion to machining and loading/unloading stations
- Fast braking and acceleration
- 360° freedom of motion
- Integration in robot controller
- Cycle time concurrent processes
- Reduces process times and error ratios
- Minimal installation expense and uncomplicated integration
RS series rotary indexers: Specially designed for rotatory motion
Nabtesco developed the RS series especially for rotatory positioning. The compact and robust hollow shaft precision gears are designed for axial loads up to 9 t, outstanding torque capacity and high-precision positioning. In combination with a servo motor, they can be used to implement freely programmable and highly flexible positioning units, which can readily be adapted to changing requirements in handling and assembly applications.
The large hollow shaft of the rotary indexers offers plenty of space for feed-through of supply cables for turning and clamping devices. It does not remain rigid, but rather is designed to rotate at the output rpm. The advantage of this is that a sensor on the hollow shaft can determine the position of the drive shaft. The cast iron base allows for easy mounting of the rotary indexers on the floor and provides for high stability. The motor is mounted at a right angle for ease of access.
The RS series at a glance:
- Five sizes: 1,5 t (RS-50A), 2,5 t (RS-260A), 5 t (RS-320A), 7 t (RS-400A), 9 t (RS-900A)
- High torsional rigidity for exact positioning in dynamic cycles
- Reduced cycle times due to high-speed rotation
- Compact design
- Large hollow shaft for feed-through of supply cables for turning and clamping devices
- Compatible with all standard servo motors
- Sturdy, robust construction
- Uncomplicated mounting and convenient handling
Would you like to learn more about RS series rotary indexers, or do you have questions about a particular application? Do not hesitate to contact our experts.
