DFC Aluminum Curved Jaw Coupling – Zero Backlash, High Torque for Servo Motors & Ball Screws

Factory direct | High-strength aluminum alloy | Zero backlash | German polyurethane spider | 12.9 grade screws | Anodized finish | 19000 RPM | OEM/ODM/OBM

The Apexcoupling DFC series is a high-performance aluminum curved jaw coupling (spider/plum coupling) engineered for precision motion control in servo motors, stepper motors, and ball screw drives. Featuring zero rotational clearance, this coupling is ideal for applications requiring positive and negative rotation with absolute precision. Constructed from high-strength aluminum alloy with a German imported polyurethane spider, it offers excellent wear resistance, oil resistance, electrical insulation, and vibration damping. The detachable design with clamping screw fastening ensures easy installation and maintenance. With its lightweight construction and low inertia, the DFC series delivers superior performance in CNC machines, robotics, packaging machinery, and automation equipment.

✅ Zero backlash – ideal for servo and stepper motors. Lightweight aluminum reduces inertia for rapid acceleration. German polyurethane spider absorbs vibration and compensates for misalignment. Maintenance-free – no lubrication required.

Key Technical Specifications

🔧 Custom bores, keyways, spider hardness (different durometers available), and anodizing colors available. Contact us with your specifications.

Product Structure

1. Two Aluminum Hubs – High-strength aluminum alloy, precision-machined with curved jaws, anodized finish.

2. German Polyurethane Spider – The elastic insert that transmits torque, absorbs shock, and compensates for misalignment.

3. Clamping Screws (12.9 Grade) – Secure shaft fastening with even clamping force.

💡 The curved jaw profile ensures a press-fit with the spider, eliminating backlash and providing smooth, precise torque transmission. The curved tooth design provides greater contact area for higher torque capacity in a compact design . The three-piece construction allows for quick spider replacement without moving the hubs .

Product Features & Advantages

Why Choose a Curved Jaw Coupling for Servo Applications?

The DFC series is specifically designed for high-precision servo and stepper motor applications. The unique curved jaw design, combined with the pre-loaded polyurethane spider, provides a zero-backlash connection that maintains the same angular relationship between input and output shafts without lost motion .

Zero-backlash curved jaw couplings are best suited for applications that rely on stop-and-go movement, where accuracy needs to take place upon stopping – such as CNC machining, robotics, and machine vision systems . The polyurethane spider absorbs vibrations, decreasing the settling time the system needs and increasing throughput .

Key benefits for servo systems:

• Zero backlash – No lost motion, precise positioning

• Low inertia – Lightweight aluminum enables rapid acceleration and deceleration

• Vibration damping – Reduces settling time and improves system stability

• Misalignment compensation – Protects bearings and seals from misalignment damage 

Applications

• Servo Motors – High-precision motion control, zero backlash requirement

• Stepper Motors – Accurate positioning, no lost motion

• Ball Screw Drives – Smooth, accurate linear positioning

• CNC Machine Tools – Spindle drives, feed axes, high-precision positioning

• Robotics – Joint drives, precision motion control

• Packaging Machinery – Registration and indexing systems

• 3D Printers – Lightweight, precise filament drive and positioning 

• Semiconductor Equipment – High precision, clean room compatible

• Printing Machinery – Register control, high-speed operation

• Automation Equipment – Pick-and-place systems, indexing tables

Why Choose Apex Coupling for DFC Couplings?

FAQ

Q: What is a curved jaw coupling?
A: A curved jaw coupling (also called a spider coupling, jaw coupling, or plum coupling) consists of two aluminum hubs with curved jaws and a polyurethane spider element. The curved jaw profile ensures zero backlash operation .

Q: What does “zero backlash” mean?
A: Zero backlash means there is no rotational clearance between the hubs and the spider. This ensures precise torque transmission with no lost motion – critical for servo motors, stepper motors, and precision positioning .

Q: What materials are used?
A: The hubs are made of high-strength aluminum alloy (aviation-grade 6061 available) with optional anodized finish . The spider is made of German imported polyurethane – wear-resistant, oil-resistant, and electrically insulating .

Q: What is the maximum speed?
A: Maximum speed is 19000 RPM – suitable for high-speed precision applications.

Q: What spider materials and hardnesses are available?
A: Standard is polyurethane with different durometers available (red/hard, yellow/medium, blue/soft) for different response speed and damping requirements .

Q: Can the coupling compensate for misalignment?
A: Yes. The polyurethane spider compensates for radial, angular, and axial deviations .

Q: Is the coupling easy to install?
A: Yes. The detachable design allows for easy installation and maintenance without moving connected shafts.

Q: Does the coupling require lubrication?
A: No. The DFC series is maintenance-free – no lubrication required .

Q: What is the clamping screw design?
A: The clamping screw design uses tightening screws to compress the hub onto the shaft, providing secure fixation with even clamping force and no shaft damage.

Q: Can I get a custom coupling?
A: Yes. We offer OEM, ODM, and OBM support – custom bores, keyways, spider hardness, anodizing colors, and branding available.

Request a Quote

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