Flange star elastic couplings are essential for heavy-duty industrial applications requiring zero-backlash torque transmission and secure flange connections. The DJ-SF (double flange) and DJ-DF (single flange) series from Apex Coupling offer two configurations to suit different mounting requirements, with torque ratings from 35 to 18650 N·m.

This guide explains how flange star elastic couplings work, the advantages of each configuration, and how to select the right model for your application.

1. What Is a Flange Star Elastic Coupling?

A flange star elastic coupling consists of:

• Two hubs – precision-machined from 45# steel (one or both flanged)

• A star-shaped polyurethane elastomer – provides zero-backlash torque transmission and vibration damping

• Flange connection – secures the coupling to heavy machinery

The star-shaped elastomer transmits torque while absorbing shock, dampening vibration, and compensating for misalignment. The flange design provides a secure connection to heavy machinery, making it ideal for demanding industrial applications.

💡 Flange star elastic couplings are widely used in heavy machinery, main spindle drives, lifting platforms, and machine tools.

2. DJ-SF (Double Flange) vs DJ-DF (Single Flange) – Which One Do You Need?

✅ Choose DJ-SF (double flange) when: You need quick elastomer replacement without moving connected equipment – simply remove the flange and install radially.

3. Double Flange Advantage – Radial Installation

The double flange structure (DJ-SF) offers a significant maintenance advantage:

4. Key Advantages of DJ-SF/DF Couplings

5. How to Select the Right Model

Step 1: Choose the Configuration

• DJ-SF (Double Flange): Radial installation, quick maintenance, tight spaces.

• DJ-DF (Single Flange): Standard flange-to-shaft connection.

Step 2: Determine Your Torque Requirement

• Calculate the torque your application requires.

• Select a model with rated torque ≥ 1.5× your requirement.

• DJ-SF/DF series covers 35–18650 N·m.

Step 3: Match Shaft Diameters

• Measure your shaft diameters.

• Select a model with a bore range that accommodates your shafts.

• H7 bore tolerance is recommended for precision fit.

Step 4: Consider Speed Requirements

• Verify the coupling’s maximum speed exceeds your operating speed.

• DJ-SF/DF series offers speeds up to 14000 RPM.

Step 5: Consider Space Constraints

• Measure available space for the coupling (outer diameter and flange diameter).

• DJ-SF/DF series offers compact sizes from 55 mm OD.

Step 6: Consider Keyway Requirements

• For applications requiring keyways, specify when ordering.

6. Applications Where DJ-SF/DF Couplings Excel

7. Real‑World Example – Heavy Machinery Upgrade

A heavy machinery manufacturer was experiencing downtime due to difficult elastomer replacement on their existing couplings. The standard flange couplings required disassembly of connected equipment for maintenance.

They switched to Apex Coupling DJ-SF double flange star coupling (radial installation, quick elastomer replacement). Results:

• Maintenance time reduced – radial installation without moving equipment

• Downtime reduced – quick elastomer replacement

• Performance improved – zero backlash

• Maintenance eliminated – no lubrication required

8. Installation & Maintenance Tips

1. Choose the right type – DJ-SF for radial installation without moving equipment.

2. Clean flanges – Remove debris before installation.

3. Check alignment – Even with misalignment compensation, keep within recommended limits.

4. No lubrication required – Coupling is maintenance-free.

5. Periodic inspection – Check elastomer condition periodically.

6. Quick replacement – For DJ-SF, replace elastomer radially without moving equipment.

9. Selection Checklist

• □ 

  Type: DJ-SF (double flange) or DJ-DF (single flange)

• □ 

  Model: DJ24F to DJ180F – select based on torque and bore requirements

• □ 

  Material: 45# steel – high strength, durable

• □ 

  Backlash: Zero backlash – precision applications

• □ 

  Bore: H7 tolerance – match your shaft diameters

• □ 

  Torque: 35-18650 N·m – ensure it exceeds your requirement

• □ 

  Speed: Up to 14000 RPM – match your motor speed

• □ 

  Maintenance: Maintenance-free – no lubrication

• □ 

  Application: Heavy machinery, machine tools, lifting platforms, compressors

10. Conclusion

The DJ-SF (double flange) and DJ-DF (single flange) star elastic couplings from Apex Coupling offer the perfect combination of zero backlash, secure flange connection, and flexible mounting options for heavy-duty industrial applications. With 35-18650 N·m torque capacity and double flange radial installation for quick maintenance, they are the ideal solution for heavy machinery, main spindle drives, lifting platforms, and machine tools.

👉 Need a flange star elastic coupling for your application? Contact us with your type, model, bore, and torque requirements.