DF Curved Jaw Coupling | Zero Backlash, 1.1-109 N·m, 19000 RPM

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DF Series Curved Jaw Coupling – Zero Backlash, 1.1-109 N·m, 19000 RPM

Model Number
Check below, custom

DF-14×22

DF-20×25

DF-20×30

DF-25×34

DF-30×35

DF-40×55

DF-40×66

DF-55×78

DF-65×90

Product Description

DF Series Curved Jaw Coupling – Zero Backlash, High Speed, Replace Lovejoy®

The Apexcoupling DF series is a high-precision curved jaw coupling engineered for demanding motion control applications. Featuring a high-strength aluminum alloy body and a polyurethane spider element, this coupling delivers zero backlash torque transmission with excellent vibration damping and misalignment compensation. The curved jaw design provides uniform load distribution, reducing stress concentrations and extending service life. The polyurethane spider is resistant to oil, dirt, sand, grease, moisture, solvents, and ozone – making it ideal for harsh industrial environments. With clamping screw fastening, H7 precision bore, and maintenance-free operation, the DF series is the ideal solution for servo motors, stepper motors, encoders, lead screws, and precision automation equipment. A direct replacement for Lovejoy® couplings, the DF series offers the same performance at factory-direct pricing.

✅ Zero backlash – no lost motion for precise positioning. Oil, dirt, moisture, and solvent resistant – durable in harsh environments. High-strength aluminum alloy – lightweight and corrosion-resistant. Polyurethane spider – excellent damping and wear resistance. Maintenance-free – no lubrication required. Direct Lovejoy® replacement – same performance, better value.

Key Technical Specifications

Parameter	Value
Brand	Apexcoupling
Model Series	DF (Curved Jaw Coupling)
Type	Flexible / Jaw / Spider
Structure	Curved jaw – two hubs + polyurethane spider
Body Material	High-strength aluminum alloy
Spider Material	Polyurethane (PU) – oil, dirt, moisture, solvent, and ozone resistant
Surface Treatment	Anodized
Backlash	Zero – no rotational clearance
Bore Tolerance	H7
Bore Diameter Range	3 – 38 mm (custom available)
Outer Diameter Range	14 – 65 mm
Length Range	22 – 90 mm
Rated Torque	1.1 – 109 N·m
Maximum Speed	6000 – 19000 RPM (varies by model)
Allowable Eccentricity	0.02 mm
Allowable Deflection Angle	1°
Allowable Axial Deviation	±0.6 to ±0.8 mm
Misalignment Compensation	Angular, radial (eccentricity), and axial
Fastening Method	Clamping screw (positioning screws)
Maintenance	None required – maintenance-free
Operating Temperature	-30°C to +100°C
Compatible With	Lovejoy® L series, jaw couplings
Customization	OEM – custom bores, keyways, and materials
Applicable Industries	Servo motors, stepper motors, encoders, lead screws, CNC machines, robotics, construction machinery, automation equipment
Place of Origin	Guangdong, China

🔧 Custom bores and keyways available. For keyway options, add “K” after the shaft diameter (e.g., DF-20×30-8Kx9K). Contact us with your specifications.

DF Series – Model Range & Specifications

Model	Outer Diameter (D) mm	Length (L) mm	Bore Range (d) mm	Rated Torque (N·m)	Max Speed (RPM)	Weight (g)
DF-14×22	14	22	3,4,5,6,6.35,7	1.1	19000	7
DF-20×25	20	25	4,5,6,6.35,7,8,9,9.525,10	2.8	17000	13
DF-20×30	20	30	4,5,6,6.35,7,8,9,9.525,10	2.8	17000	18
DF-25×34	25	34	4,5,6,6.35,7,8,9,9.525,10,11,12	6	16000	30
DF-30×35	30	35	5,6,6.35,7,8,9,9.525,10,11,12,14,15,16	6.5	12000	46
DF-40×55	40	55	8,9,9.525,10,11,12,12.7,14,15,16,19,20,22,24	32	10000	120
DF-40×66	40	66	8,9,9.525,10,11,12,12.7,14,15,16,19,20,22,24	32	10000	145
DF-55×78	55	78	12,12.7,14,15,16,19,20,22,24,25,25.4,28,30	46	8000	320
DF-65×90	65	90	14,15,16,19,20,22,24,25,25.4,28,30,35,38	109	6000	560

📐 Additional sizes and custom dimensions available upon request. Contact our engineering team for custom sizing.

Model Designation – DF Series

DF-□□×□□-□□×□□

Position	Meaning	Example
DF	Series code – Curved Jaw Coupling	DF
□□×□□	Outer Diameter (D) × Length (L)	20×30
□□×□□	Inner Diameter 1 (d1) × Inner Diameter 2 (d2)	8×9

Keyway Option: Add “K” after the shaft diameter for keyway.

Example: DF-20×30-8K×9K – both bores with keyways

Product Structure

Two Aluminum Hubs – High-strength aluminum alloy, precision-machined with curved jaws, anodized finish.
Polyurethane Spider – The elastic insert that transmits torque, absorbs shock, and compensates for misalignment.
Clamping Screw Fastening – Secure shaft fixation with even clamping force.

💡 How it works: The DF coupling consists of two aluminum hubs with curved jaws and a polyurethane spider. The spider is inserted between the jaws, and torque is transmitted through the spider, which flexes to absorb shock, dampen vibration, and compensate for misalignment. The curved jaw design provides uniform load distribution, reducing stress concentrations and extending spider life. The zero backlash design ensures precise positioning – making it ideal for servo and stepper motor applications. The spider is resistant to oil, dirt, sand, grease, moisture, solvents, and ozone.

Product Features & Advantages

Advantage	Benefit
Zero Backlash	No rotational clearance – precise positioning for encoders and servo motors
Curved Jaw Design	Uniform load distribution – reduces stress concentrations, extends spider life
Polyurethane Spider	Excellent vibration damping, wear resistance, and oil/dirt resistance
Oil, Dirt & Moisture Resistant	Resistant to oil, dirt, sand, grease, moisture, solvents, and ozone
High-Strength Aluminum Alloy	Lightweight, corrosion-resistant, high strength-to-weight ratio
High Speed Capability	Up to 19000 RPM – suitable for high-speed applications
Clamping Screw Fastening	Even clamping force, no shaft damage – easy installation
H7 Precision Bore	High concentricity and accurate shaft fit – reduces vibration
Detachable Design	Easy installation and maintenance – replace spider without moving hubs
Maintenance-Free	No lubrication required – reduces operating costs
Lovejoy® Replacement	Direct replacement – no design changes required
OEM Customization	Custom bores, keyways, and materials available

Lovejoy® Replacement – Same Performance, Better Value

The DF series is a direct replacement for Lovejoy® jaw couplings:

Feature	DF Series (Apex)	Lovejoy® Series
Design	Curved jaw coupling	Curved jaw coupling
Hub Material	High-strength aluminum alloy	Aluminum alloy
Spider Material	Polyurethane	Polyurethane
Zero Backlash	✅ Yes	✅ Yes
Interchangeable	✅ Yes – direct replacement	–
Pricing	Factory direct	Premium

✅ The DF series is a direct replacement for Lovejoy® – offering the same performance, same dimensions, and better value.

Applications

Servo Motors – High-precision motion control systems
Stepper Motors – Accurate positioning and step transmission
Encoders – Precision position feedback systems
Lead Screws – Precision linear motion systems
CNC Machines – Feed drives, positioning systems
Robotics – Joint drives, precision motion
Construction Machinery – Heavy-duty power transmission
Automation Equipment – Pick-and-place systems, indexing tables
Pumps & Compressors – Light to medium-duty drives

Why Choose Apex Coupling for DF Curved Jaw Couplings?

Advantage	Description
Factory Direct	Competitive B2B pricing – no middlemen
Premium Aluminum Alloy	Lightweight, corrosion-resistant, high strength
Zero Backlash	Precision performance for encoders, servo motors, and stepper motors
Polyurethane Spider	Excellent damping, wear resistance, oil/dirt resistance
High Speed Capability	Up to 19000 RPM – suitable for high-speed applications
Clamping Screw Fastening	Secure, even clamping force – no shaft damage
H7 Precision Bore	High concentricity and accurate shaft fit
Maintenance-Free	No lubrication required – reduces operating costs
Lovejoy® Replacement	Direct replacement – no design changes required
OEM Customization	Custom bores, keyways, and materials available

FAQ

Q: What is a curved jaw coupling?
A: A curved jaw coupling consists of two aluminum hubs with curved jaws and a polyurethane spider. It transmits torque while absorbing shock, dampening vibration, and compensating for misalignment with zero backlash.

Q: What is the advantage of the curved jaw design?
A: The curved jaw design provides uniform load distribution across the spider, reducing stress concentrations and extending spider life compared to straight-jaw designs.

Q: What materials are used?
A: The hubs are made of high-strength aluminum alloy with anodized finish. The spider is made of polyurethane (PU) – resistant to oil, dirt, sand, grease, moisture, solvents, and ozone.

Q: Does the coupling have backlash?
A: No. The DF series features zero backlash – no rotational clearance, ensuring precise positioning for encoders and servo motors.

Q: Is the coupling maintenance-free?
A: Yes. The DF series is maintenance-free – no lubrication required.

Q: What are the common applications?
A: Servo motors, stepper motors, encoders, lead screws, CNC machines, robotics, and automation equipment.

Q: Is this a replacement for Lovejoy® couplings?
A: Yes. The DF series is a direct replacement for Lovejoy® jaw couplings – same dimensions, same performance, better value.

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

Q: Can I get a custom coupling?
A: Yes. We offer OEM customization – custom bores, keyways, and materials available. For keyway options, add “K” after the shaft diameter (e.g., DF-20×30-8K×9K).

Q: What is the maximum speed?
A: Maximum speed ranges from 6000 to 19000 RPM depending on the model.

Request a Quote

Send us your model (e.g., DF-25×34), bore size, torque, speed, and application details. Our engineers will recommend the optimal model and provide a quotation within 24 hours.