Combines precision, rigidity, and durability

Sumitomo Drive Technologies is expanding its portfolio of zero-backlash precision gearboxes with the B Series of the Fine Cyclo family. This new series is aimed at manufacturers and design engineers seeking to implement compact drive solutions characterized by high dynamics and maximum transmission accuracy – particularly in applications involving confined installation spaces and stringent requirements for stiffness and rotational accuracy, such as those found in machine tools, medical technology, or handling systems.
Compact in Diameter. Big on Performance.

The Fine Cyclo B Series combines a compact design with supreme precision and high power density. This newly developed series, featuring Cyclo technology, covers outer diameters ranging from 120 to 231 millimeters and transmits acceleration torques of 417 to 4,000 Newton-meters. In overload situations, peak torques of up to 8,000 Newton-meters (emergency stop) are achievable.

Rotational and axial run-out in the micrometer range, high torsional stiffness, and exceptional transmission accuracy ensure precise and dynamic movements, even under the most demanding conditions.

Thanks to its single-stage design and wide reduction ratio range (29–179:1), the B Series can be integrated into machinery with exceptional space efficiency. Furthermore, the modular drive system facilitates rapid and standardized adaptation to various motor and interface configurations.

"The new B Series supports highly dynamic applications without requiring users to compromise on accuracy, stiffness, load capacity, or performance," says Michael Berger, Product Manager and Team Lead for Business Development at Sumitomo Drive Technologies. He adds: "Two variants – each comprising four frame sizes with up to five different reduction ratios – allow for precise customization to suit any specific application." Two Variants for Diverse Integration and Load Requirements

The series comprises two versions designed to meet a range of distinct requirements:

• F4C-B "Main Bearing Type" – Plug & Play Gearbox for Robust Precision Axes

The F4C-B variant, featuring an integrated main bearing, stands out thanks to its exceptionally high rigidity, peak torque capacity, and precise transmission accuracy—entirely free of mechanical backlash.

As a plug & play solution, these gearboxes come factory-filled with lifetime lubrication and are fully sealed, rendering them maintenance-free and ready for immediate use.

The integrated angular contact ball bearings are dimensioned to handle the heaviest loads, ensuring reliable load support, while precise radial and axial run-out at the output guarantees precise motion execution and secure application integration.

The four available frame sizes, featuring graduated reduction ratios, allow for flexible configuration to suit various automation tasks; they are particularly well-suited for applications where rigidity, precise transmission, and reliable load support are the primary focus.

• FC-B "KIT Type" – Modular Precision Gearbox for Custom Machine Solutions

This gearbox kit offers maximum design freedom for customer-specific machine concepts. It focuses on the core function of precise torque transmission, enabling application-specific configurations—particularly in cases where integration and interfaces are individually defined by the customer.

The kit is available in four frame sizes (B15, B25, B35, B45) with a wide range of reduction ratios—reaching up to 179:1 in the single-stage configuration—and is especially suitable for highly dynamic solutions where precision, flexibility, and load-bearing capacity are critical factors.

Typical Applications

The Fine Cyclo B Series is suitable for use in the following industries, among others:

• Machine Tools: High torsional stiffness and rotational accuracy keep axes stable under load, thereby improving surface finish and manufacturing precision. 
• Medical Technology: Precise axis movements in CT or MRI scanners—combined with smooth operation—ensure stable image quality and quiet performance. 
• Packaging Machinery: A compact design, high input speeds, and maximum torque density enable short cycle times and efficient machine layouts.

With the B Series, Sumitomo Drive Technologies demonstrates how precision, dynamics, and compactness can be successfully combined within a single gearbox. This product series offers maximum flexibility within a minimal footprint, high positioning accuracy, and robust solutions for demanding automation and precision applications.
Technical Principle: Cyclo Gear Technology

The Fine Cyclo B Series utilizes proven Cyclo® technology, which enables the transmission of exceptionally high torques while ensuring smooth, vibration-free operation. An eccentric bearing mounted on the input shaft drives the cycloidal discs, which in turn precisely transmit the rotational motion to the output shaft. This operating principle minimizes mechanical backlash and ensures smooth, highly dynamic movements.