Product Description

SC Transmission FCL Flexible Shaft Couplings for Reducer and Motor


Product Description

FCL Coupling/Shaft Coupling /Pin & Bush Coupling /FCL Flexible Coupling/NBK FCL Coupling is widely used for its compacts designing, easy installation, convenient maintenance, small and light weight. 

As long as the relative displacement between shafts is kept within the specified tolerance, couplings will operate the best function and have a longer working life.

Thus it is greatly demanded in medium and minor power transmission systems driven by motors, such as speed reducers, hoists, compressors, conveyors, spinning and weaving machines and ball mills.

Product Parameters

SIZE     D D1 d1 L C n-M kg
FCL90 4 4000 90 35.5 11 28 3 4-M8 1.7
FCL100 10 4000 100 40 11 35.5 3 4-M10 2.3
FCL112 16 4000 112 45 13 40 3 4-M10 2.8
FCL125 25 4000 125 65 50 13 45 3 4-M12 4
FCL140 50 4000 140 71 63 13 50 3 6-M12 5.4
FCL160 110 4000 160 80 15 56 3 8-M12 8
FCL180 157 3500 180 90 15 63 3 8-M12 10.5
FCL200 245 3200 200 100 21 71 4 8-M20 16.2
FCL224 392 2850 224 112 21 80 4 8-M20 21.3
FCL250 618 2550 250 125 25 90 4 8-M24 31.6
FCL280 980 2300 280 140 34 100 4 8-M24 44
FCL315 1568 2050 315 160 41 112 4 10-M24 57.7
FCL355 2450 1800 355 180 60 125 5 8-M30 89.5
FCL400 3920 1600 400 200 60 125 5 10-M30 113
FCL450 6174 1400 450 224 65 140 5 12-M30 145
FCL560 9800 1150 560 250 85 160 5 14-M30 229
FCL630 15680 1000 630 280 95 180 5 18-M30 296



Company Profile



flexible coupling

How does a flexible coupling deal with backlash and torsional stiffness?

A flexible coupling deals with backlash and torsional stiffness in the following ways:

  • Backlash: Backlash refers to the play or clearance between mating teeth in mechanical systems. In certain couplings, such as gear couplings, some degree of backlash is unavoidable due to the space between the teeth. However, flexible couplings with elastomeric or beam-type elements typically have minimal to no backlash. The flexibility of these elements allows them to maintain continuous contact and transmit torque smoothly without any gaps or play between components.
  • Torsional Stiffness: Torsional stiffness is the ability of a coupling to resist rotational deformation or twisting under torque. It is essential to have adequate torsional stiffness in some applications to ensure accurate motion transmission and responsiveness. Flexible couplings exhibit a balance between torsional stiffness and flexibility. While they allow for a degree of angular and parallel misalignment, they still possess sufficient torsional stiffness to transmit most of the torque efficiently. This characteristic helps maintain the precision of motion control systems and prevents power losses due to deformation.

The design and materials used in flexible couplings contribute to their ability to address both backlash and torsional stiffness effectively. Here are some key features:

  • Elastomeric Elements: Couplings with elastomeric elements, such as rubber or polyurethane, provide excellent flexibility to absorb misalignments and dampen vibrations. They also exhibit minimal backlash as the elastomeric material maintains continuous contact between the coupling components.
  • Beam-Type Couplings: Beam-type couplings use thin metal beams to transmit torque. These couplings offer high torsional stiffness while still accommodating misalignments. The beams can flex slightly under torque, absorbing shocks and compensating for misalignment without compromising torsional rigidity.
  • Composite Couplings: Some flexible couplings use composite materials that combine the advantages of different materials to achieve specific performance characteristics. These composites can offer low backlash and precise torsional stiffness, making them suitable for demanding applications.
  • High-Quality Manufacturing: The precision manufacturing of flexible couplings ensures that components fit together with minimal clearances, reducing backlash. Additionally, high-quality materials contribute to better torsional stiffness and overall performance.

Overall, flexible couplings strike a balance between flexibility to accommodate misalignments and sufficient torsional stiffness to transmit torque efficiently. By effectively addressing backlash and torsional stiffness, these couplings contribute to the smooth and reliable operation of various mechanical systems.

flexible coupling

Can flexible couplings be used in high-temperature environments, such as furnaces and kilns?

Flexible couplings can be used in high-temperature environments, such as furnaces and kilns, but the selection of the appropriate coupling is crucial to ensure reliable performance and longevity under these extreme conditions. Here are some key considerations:

  • Material Selection: The choice of materials is critical when using flexible couplings in high-temperature applications. Look for couplings made from heat-resistant materials that can withstand the elevated temperatures without experiencing significant degradation. Common materials used for high-temperature couplings include stainless steel, high-temperature alloys, and certain types of elastomers designed for heat resistance.
  • Lubrication: High temperatures can cause lubricants to break down or evaporate more quickly. Some flexible couplings may require specialized high-temperature lubricants to ensure smooth operation and reduce wear at elevated temperatures. Check the manufacturer’s recommendations for lubrication in high-temperature environments.
  • Thermal Expansion: In high-temperature applications, the equipment and shafts may experience thermal expansion, leading to misalignment. Flexible couplings with higher misalignment capabilities may be necessary to accommodate these thermal effects and prevent additional stress on the system.
  • Torsional Stiffness: Consider the required torsional stiffness for the specific application. In high-temperature environments, couplings may experience changes in stiffness due to temperature variations. It is essential to choose a coupling with appropriate torsional characteristics for the intended operating temperature range.
  • Application Specifics: Evaluate the specific operating conditions of the furnace or kiln, including the maximum and fluctuating temperatures, vibration levels, and potential exposure to chemicals or other harsh elements. Choose a coupling that can withstand these conditions without compromising performance or safety.
  • Coupling Type: Different types of flexible couplings offer varying degrees of heat resistance and performance capabilities. For example, certain types of disc couplings or metal bellows couplings are more suitable for high-temperature environments due to their robust construction and resistance to heat.
  • Regular Maintenance: In high-temperature applications, couplings may be subject to more stress and wear. Regular inspection and maintenance are essential to monitor the coupling’s condition, lubrication, and alignment to ensure it continues to function optimally in the challenging environment.

Overall, flexible couplings can be utilized in high-temperature environments, but it is vital to choose a coupling specifically designed and rated for these conditions. Working closely with coupling manufacturers and considering the specific demands of the application will help ensure that the selected coupling can handle the challenges posed by furnaces, kilns, and other high-temperature equipment, providing reliable power transmission and contributing to the overall efficiency and safety of the system.

flexible coupling

Can flexible couplings be used for both motor-to-shaft and shaft-to-shaft connections?

Yes, flexible couplings can be used for both motor-to-shaft and shaft-to-shaft connections in various applications. The versatility of flexible couplings allows them to adapt to different types of connections and meet the specific requirements of the system.

Motor-to-Shaft Connections:

When connecting a motor to a shaft, a flexible coupling serves as an intermediary component that joins the motor shaft and the driven shaft. Flexible couplings are commonly used in motor-driven systems to accommodate misalignment between the motor and the driven load. In motor applications, flexible couplings help reduce stress and wear on the motor bearings, thus extending the motor’s life and enhancing overall system reliability. They also act as vibration dampeners, minimizing vibrations transmitted from the motor to the driven shaft, and subsequently to connected equipment, ensuring smoother operation.

Shaft-to-Shaft Connections:

In many mechanical systems, such as those in the manufacturing, automation, and power transmission industries, shaft-to-shaft connections are required. A flexible coupling can bridge the gap between two shafts and transmit torque while accommodating misalignment. This type of coupling is commonly used to connect shafts that are not perfectly aligned due to factors like manufacturing tolerances, thermal expansion, or foundation settling. By allowing for misalignment, the flexible coupling protects the connected components from excessive stresses and ensures efficient power transmission.

Versatility and Advantages:

The ability of flexible couplings to handle both motor-to-shaft and shaft-to-shaft connections makes them versatile solutions for a wide range of industrial applications. Some of the advantages of using flexible couplings in these connections include:

  • Minimizing stress and wear on connected components, such as bearings and seals.
  • Compensating for misalignment, ensuring smooth power transmission.
  • Damping vibrations and shock loads, reducing the risk of mechanical failures.
  • Protecting equipment from excessive forces, enhancing system reliability.
  • Simplifying installation and alignment procedures, reducing downtime.
  • Improving overall system performance and operational efficiency.


Flexible couplings find applications in a wide range of industries, including manufacturing, material handling, automotive, aerospace, robotics, and more. Whether connecting a motor to a shaft or joining two shafts directly, flexible couplings play a crucial role in enhancing the reliability and efficiency of rotating machinery and mechanical systems.

In conclusion, flexible couplings can effectively serve as connectors for both motor-to-shaft and shaft-to-shaft connections, providing essential misalignment compensation and protection for connected equipment in various industrial applications.

China OEM FCL Flexible Shaft Couplings for Reducer and Motor  China OEM FCL Flexible Shaft Couplings for Reducer and Motor
editor by CX 2023-11-09