DJM Single Disc Elastic Diaphragm Coupling – Keyway Type, High Torque, Zero Backlash

Factory direct | 45# steel or high-strength alloy steel | 304 stainless steel diaphragm | Zero backlash | High torsional rigidity | Keyway connection | Black oxide or anodized finish | OEM/ODM/OBM

The Apexcoupling DJM series is a high-performance single disc elastic diaphragm coupling engineered for precision power transmission in demanding industrial applications. Featuring a keyway connection with hinge-fit bolt holes for zero clearance, this coupling delivers high strength, reliable connection, and sensitive response. Constructed from 45# steel with a 304 stainless steel diaphragm, the DJM series offers excellent torque capacity, vibration damping, and misalignment compensation. The diaphragm structure compensates for radial, angular, and axial deviations through elastic deformation, making it ideal for pumps, compressors, servo motors, stepper motors, and general industrial machinery.

✅ Zero backlash, high torsional rigidity, and maintenance-free operation – commonly used in servo motors, stepper motors, and high-precision transmission systems.

Key Technical Specifications

🔧 Custom bores, keyways, materials, and surface finishes available. Contact us with your specifications.

DJM Series – Model Range (Reference)

📐 Custom bores and non-standard sizes available upon request.

Product Structure

1. Two Hubs – Precision-machined from 45# steel with keyway connection for high-strength shaft attachment.

2. 304 Stainless Steel Diaphragm – Single disc design with elastic deformation capability, available in connecting rod type or integral type.

3. Hinge-Fit Bolts – Tight-fitting bolt holes with no clearance for zero backlash operation.

4. Surface Treatment – Black oxide finish (standard) for corrosion resistance.

💡 How it works: The DJM coupling consists of several groups of stainless steel diaphragms connected to the two hub halves by alternating bolts. As the coupling rotates, the diaphragm elastically deforms to compensate for radial, angular, and axial misalignment between shafts. The keyway connection ensures high strength and reliable power transmission.

Product Features & Advantages

Applications

• Servo Motors & Stepper Motors – Precision motion control, zero backlash requirement

• Pumps – Centrifugal pumps, chemical pumps, high-power pumps

• Compressors – Air and gas compressors

• Fans & Blowers – Industrial ventilation systems

• Printing Machinery – High-precision register control

• Textile Machinery – High-speed, precision drives

• Chemical Machinery – Corrosion-resistant applications

• Mining & Metallurgical Equipment – Heavy-duty power transmission

• Marine & Shipboard Equipment – Marine propulsion, shipboard pumps

• Power Generation – High-speed, high-power mechanical transmission systems

• Aerospace – High-precision, high-reliability applications

Why Choose Apex Coupling for DJM Diaphragm Couplings?

FAQ

Q: What is a DJM diaphragm coupling?
A: The DJM is a single disc elastic diaphragm coupling that uses stainless steel diaphragms to transmit torque while compensating for misalignment. It features a keyway connection with hinge-fit bolts for zero backlash operation.

Q: What is the advantage of the keyway connection?
A: The keyway connection provides high strength and bearing capacity, ensuring reliable power transmission. The hinge-fit bolt holes have no clearance, eliminating backlash.

Q: What materials are used?
A: The hubs are made of 45# steel (standard) with black oxide finish. The diaphragm is made of 304 stainless steel for excellent corrosion resistance and fatigue resistance.

Q: Does the coupling have backlash?
A: No. The DJM series features zero backlash – no rotational clearance, ensuring precise positioning for servo motors, stepper motors, and high-precision applications.

Q: What misalignment can the coupling compensate for?
A: The diaphragm elastically deforms to compensate for radial, angular, and axial deviations between shafts.

Q: Does the coupling require lubrication?
A: No. The DJM series is maintenance-free – no lubrication required. The metal diaphragm transmits torque without sliding or friction parts.

Q: What are the rotation characteristics?
A: Clockwise and counterclockwise rotation characteristics are exactly the same – ideal for reversing applications.

Q: What is the torque and speed range?
A: The DJM series covers 9.8 to 15,280 N·m torque and 5,000 to 20,000 RPM speed, depending on the model.

Q: Can I get a custom coupling?
A: Yes. We offer OEM, ODM, and OBM support – custom bores, keyways, materials, and finishes available.

Request a Quote

Send us your model or bore size, torque, speed, and application details. Our engineers will recommend the optimal model and provide a quotation within 24 hours.