Table of Contents
1. Introduction: Paguflex – Synonym of Reliability and Controlled Flexibility
The Paguflex shaft coupling stands as a technically advanced solution for torque transmission in demanding industrial environments. Designed to effectively connect two rotating shafts, Paguflex not only transmits power but also functions as a crucial protective element for the entire mechanical system. Its engineered flexibility helps compensate angular, radial, and axial misalignments while damping torsional vibrations and shocks — all essential for machine longevity.
2. Paguflex Loop Coupling Materials
The durability and performance of the Double-Loop Coupling derive from carefully selected, high-quality materials engineered for dynamic loads and challenging operating environments:
• Elastic Element – Dual Performance Materials
- Polyurethane (PUR): A standard choice for many Paguflex versions, this material offers excellent wear resistance and flexibility. It performs reliably in general applications requiring good vibration damping and mechanical resilience.
- Thermoplastic Elastomer Hytrel® (TEEE) by DuPont: Used in high-performance variants, Hytrel® delivers superior dynamic stiffness and outstanding reverse-bend fatigue resistance. It broadens the operational temperature range and enhances chemical resistance, ensuring stable behavior even under frequent reversals or rapid load cycles.
These elastomer components are what make this product an effective Urethan Flexible Coupling solution for diverse industrial needs.
• Hubs / Bosses – Strength and Protection
Hubs are made from hardened or galvanized steel and receive corrosion-resistant surface treatment. Rounded, chamfered edges protect the elastic element from cuts or abrasion, increasing the coupling’s operational reliability.
• Shaft Fixing – Secure Mounting
Shaft attachment is typically via robust hex-socket set screws (e.g., DIN 916), enabling secure clamping without complex shaft keyways. This keyless method simplifies installation and reduces assembly time.
• Special Hub Configurations:
For harsher conditions — such as food & beverage, chemical environments, or applications with stray currents (e.g., inverter drives) — stainless-steel hubs are available, offering enhanced chemical resistance and inherent electrical insulation.
3. Key Technical Specifications: The Details That Matter
Paguflex specifications reflect engineering focused on reliability and wide operational versatility:
• Extended Operating Temperature Range
- Standard polyurethane versions typically operate from -30 °C to +80 °C.
- Versions with Hytrel® broaden this range, supporting extremes from approximately -40 °C to +100 °C.
• Misalignment Capacity:
- Angular Misalignment: Up to approximately ±15° in certain configurations.
- Radial Misalignment: Up to approximately ±3 mm on Paguflex PLUS models.
- Axial Displacement: Typically between 10 and 20 mm, accommodating thermal or structural shifts.
• Maximum Speed and Torque: Depending on size and model, these couplings handle speeds up to 3,000 rpm and a broad range of torque ratings (for example, around 0.8 Nm for the smallest size), increasing with larger models.
• Chemical and Environmental Resistance:
The Hytrel® elastomer exhibits strong resistance against industrial oils, common solvents, ozone (important in electric motor environments), and many acids/alkalis, extending service life in contaminated environments.
• Backlash-Free Transmission:
Critical for positioning and control applications (e.g., servo drives), Paguflex ensures quiet operation and precise motion transfer without significant wear.
4. Construction, Structural Design, and Mechanical Benefits
The effectiveness of Paguflex lies in its structural engineering:
• Double-Loop / “Twisted-8” Geometry:
This advanced double-loop design of the elastic element allows high torsional flexibility while delivering excellent damping and elastic recovery. Torque is transmitted via a curved path rather than direct compression alone.
• Non-Metallic Coupling Interface:
Eliminating metal-to-metal contact removes the need for lubrication, lowers maintenance costs, improves cleanliness, and reduces structure-borne noise.
• Drop-In Installation Capability:
Most designs enable installation or replacement without moving or realigning shafts, significantly lowering machine downtime in service situations.
• Vibration and Shock Protection:
The damping behavior helps shift system resonance frequencies out of the motor’s operating range, preventing structural damage from harmonic vibration.
5. Material Specifications and Optimal Configuration Options
The Paguflex lineup offers configuration flexibility to meet specific industrial demands:
• Shore Hardness and Stiffness:
Elastic elements come in different Shore hardness options. Softer grades maximize damping, while harder grades provide greater torsional stiffness and precision — ideal for applications like servo drives where rigidity is critical.
• Hub Choices for Environment:
- Galvanized Steel (Standard): Suitable for dry industrial environments with good corrosion resistance.
- Stainless Steel (Optional): Essential for high humidity, salt spray (marine), or frequent washdown situations, extending lifetime in aggressive environments.
• Shaft Interface and Tolerances:
Paguflex couplings come in a wide range of standard bore sizes (metric and inch) and tight tolerances, ensuring firm, concentric engagement with shafts.
6. Recommended Selection and Sizing Guidelines
To ensure the maximum service life and performance of the Paguflex Coupling, it is essential to follow a strict sizing procedure:
- Shaft Interface: Confirm the shaft diameter and the type of fastening (keyway, locking assembly, or screw clamping) compatible with the Paguflex hub.
- Maximum Torque and Service Factor: Do not only consider the nominal torque of the motor, but apply a Service Factor (Fs) that takes into account the type of load (uniform, medium, heavy) and the operating duration. The basic formula is: Selection Torque = Nominal Torque x Fs.
- Critical Speed: Verify that the maximum rotational speed is well below the limit of the chosen coupling and, especially, that it does not approach the system’s resonance frequencies.
- Misalignment Measurements and Tolerances: Quantify the expected misalignments (initial and operational) and ensure they fall within the maximum limits permitted by the selected Paguflex model to avoid stressing the elastomer.
- Chemical and Thermal Resistance: Select the elastomer (PUR vs Hytrel®) based on the maximum operating temperature and the presence of environmental contaminants (oils, acids, etc.).
- Special Requirements: Evaluate whether electrical isolation is necessary (opting for the stainless steel version) or if the application requires a high-inertia or fail-safe coupling (in the event of elastomer failure, the hubs must prevent immediate contact).
7. Operational Benefits for End Users
Choosing Paguflex double loop couplings delivers concrete economic and performance gains:
- Reduced Total Cost of Ownership: Maintenance-free design and longer life of adjacent components (like bearings and seals) cut ongoing costs.
- High Operational Availability: Robust construction and quick elastomer replacement minimize machine downtime.
- Protects Valuable Components: Shock and vibration absorption protects expensive motors and connected loads.
- Consistent Performance in Harsh Environments: Hytrel® versions maintain mechanical properties despite thermal and chemical stress.
- Precise and Quiet Motion: Backlash-free behavior reduces noise and improves motion quality in sensitive machines.
8. Conclusion: Your Choice for Durable Shaft Coupling
In summary, the Paguflex double loop coupling is engineered for industrial reliability. From strategic material choices to backlash-free design and easy maintenance, every feature is optimized to provide efficient, protective, and long-lasting shaft coupling performance. Selecting the right model reduces maintenance costs and enhances machine uptime.
For personalized advice, service-factor calculation for your application, info on stainless-steel hubs, or a quote, contact our technical specialists.
Learn more about Paguflex
Functions and Applications of Elastic Shaft Couplings
How to Choose a Plastic Flexible Coupling
Origin, Evolution, and Warranty of the Registered Trademark PAGUAG PAGUFLEX
New Paguflex Countertop Displays