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DW Series Aluminum Triple Diaphragm Coupling – Zero Backlash, High Rigidity for Servo & Stepper Motors

Model Number
Check below, custom

DW-19×34

DW-26×44.5

DW-34×58

DW-39×65.5

DW-44×65.5

DW-56×83

DW-68×97

DW-82×128

Product Description

DW Series Aluminum Triple Diaphragm Coupling – Zero Backlash, High Rigidity for Servo & Stepper Motors

 

Factory Direct | High-Strength Aluminum Alloy | 304 Stainless Steel Triple Diaphragm | Zero Backlash | High Torsional Rigidity | 1-80 N·m Torque | 10000 RPM | Clamping Screw Fastening | Low Inertia | Maintenance-Free | OEM Customizable

 

The Apexcoupling DW series is a high-precision aluminum triple diaphragm coupling engineered for demanding motion control applications. Featuring a high-strength aluminum alloy body and a 304 stainless steel triple diaphragm, this coupling delivers zero backlash torque transmission with high torsional rigidity and superior misalignment compensation. The triple diaphragm (three-disc) design provides enhanced compensation for angular, radial, and axial misalignment while maintaining compact dimensions. With clamping screw fasteningH7 precision bore, and maintenance-free operation, the DW series is the ideal solution for encoders, resolvers, stepper motors, servo motors, lead screws, instrumentation, small pumps, feed rollers, and light to medium-duty drive systems.

✅ Zero backlash – no lost motion for precise positioning. Triple 304 stainless steel diaphragm – superior misalignment compensation and fatigue resistance. High torsional rigidity – accurate torque transmission for servo systems. Low inertia – ideal for high-speed operation up to 10000 RPM. Maintenance-free – no lubrication required.


Key Technical Specifications

 
 
ParameterValue
BrandApexcoupling
Model SeriesDW (Triple Diaphragm Coupling)
TypeFlexible / Disc / Diaphragm
StructureTriple diaphragm (three-disc)
Body MaterialHigh-strength aluminum alloy
Diaphragm Material304 stainless steel – excellent fatigue resistance, corrosion-resistant
Surface TreatmentAnodized
DesignTwo aluminum hubs + triple 304 stainless steel diaphragms with center spacers
BacklashZero – no rotational clearance
Bore ToleranceH7 – high concentricity and precise shaft fit
Bore Diameter Range3 – 40 mm (custom available)
Outer Diameter Range19 – 82 mm
Length Range34 – 128 mm
Rated Torque1 – 80 N·m
Maximum Speed8000 – 10000 RPM (varies by model)
Allowable Eccentricity0.12 – 0.55 mm
Allowable Deflection Angle
Allowable Axial Deviation±0.20 to ±0.90 mm
Misalignment CompensationAngular, radial (eccentricity), and axial
Vibration DampingYes – diaphragm absorbs shock and dampens vibration
Fastening MethodClamping screw (positioning screws)
MaintenanceNone required – maintenance-free
Operating Temperature-30°C to +100°C (depending on application)
CustomizationOEM – custom bores, keyways, and materials
Applicable IndustriesEncoders, resolvers, stepper motors, servo motors, lead screws, instrumentation, small pumps, feed rollers, CNC machines, automation equipment
Place of OriginGuangdong, China

🔧 Custom bores and keyways available. For keyway options, add “K” after the shaft diameter (e.g., DW-26×44.5-8Kx9K). Contact us with your specifications.

DW Series – Model Range & Specifications

 
 
ModelOuter Diameter (D) mmLength (L) mmBore Range (d) mmRated Torque (N·m)Max Speed (RPM)Weight (g)
DW-19×3419343,4,5,6,6.35,7,811000018
DW-26×44.52644.55,6,6.35,7,8,9,9.525,10,111.51000045
DW-34×5834586,6.35,8,9,9.525,10,11,12,12.7,14,1531000097
DW-39×65.53965.58,9,9.525,10,11,12,12.7,14,15,16,18,19610000153
DW-44×65.54465.58,9,9.525,10,11,12,12.7,14,15,16,18,19,20,22910000189
DW-56×83568312,14,15,16,18,19,20,22,24,252510000413
DW-68×97689715,16,19,20,22,24,25,28,30,35609000641
DW-82×1288212822,24,28,30,35,38,408080001345

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

Model Designation – DW Series

DW-□□×□□-□□×□□

 
 
PositionMeaningExample
DWSeries code – Triple Diaphragm CouplingDW
□□×□□Outer Diameter (D) × Length (L)26×44.5
□□×□□Inner Diameter 1 (d1) × Inner Diameter 2 (d2)8×9

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

  • Example: DW-26×44.5-8K×9K – both bores with keyways

Product Structure

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

  2. Triple 304 Stainless Steel Diaphragms – Three diaphragm packs connected by center spacers, providing superior misalignment compensation.

  3. Center Spacers – Connect the three diaphragm packs.

  4. Clamping Screw Fastening – Secure shaft fixation with even clamping force.

💡 How it works: The DW coupling consists of two aluminum hubs connected by three 304 stainless steel diaphragms with center spacers. Torque is transmitted through the diaphragms, which flex to accommodate angular, radial, and axial misalignment while maintaining high torsional rigidity. The triple diaphragm design provides enhanced compensation for all types of misalignment compared to single or double diaphragm designs. The lengthening design is adopted to more effectively compensate radial, angular and axial deviations. The design provides zero backlash operation, which is crucial for precision control in encoders, servo systems, and automated machinery.

Triple Diaphragm vs Double Diaphragm vs Single Diaphragm – Key Differences

 
 
FeatureTriple Diaphragm (DW Series)Double Diaphragm (DL Series)Single Diaphragm (DS Series)
Radial (parallel) misalignment✅ Yes – enhanced compensation✅ Yes – superior compensation❌ Cannot accommodate
Angular misalignment✅ Yes – up to 2°✅ Yes – up to 1.5°✅ Yes – up to 1°
Axial misalignment✅ Yes – up to ±0.90mm✅ Yes – up to ±0.80mm✅ Yes – up to ±0.50mm
Torsional rigidityHighHighHigher
Space requirementLongest (multiple center spacers)LongerCompact
Misalignment compensationBestSuperiorGood
Best forApplications requiring maximum misalignment compensationApplications requiring full misalignment compensationSpace-limited, well-aligned applications

Selection guideline:

  • Choose triple diaphragm (DW) for applications requiring maximum misalignment compensation, especially where significant radial, angular, and axial deviations are expected.

  • Choose double diaphragm (DL) for applications requiring full misalignment compensation.

  • Choose single diaphragm (DS) when space is limited, high torsional rigidity is required, and shafts are well-aligned with no significant parallel misalignment.

Product Features & Advantages

 
 
AdvantageBenefit
Zero BacklashNo rotational clearance – precise positioning for encoders, servo motors, and stepper motors
Triple 304 Stainless Steel DiaphragmEnhanced misalignment compensation – accommodates angular, radial, and axial misalignment with maximum effectiveness
High Torsional RigidityAccurately controls shaft rotation – enables high-precision control for servo systems
High-Strength Aluminum AlloyLightweight, low inertia – ideal for high-speed operation up to 10000 RPM
Zero-Clearance Shaft ConnectionSuitable for positive and negative rotation – identical clockwise and counterclockwise characteristics
Low InertiaLightweight design enables high-speed operation and quick starts/stops
Clamping Screw FasteningEven clamping force, no shaft damage – easy installation
H7 Precision BoreHigh concentricity and accurate shaft fit – reduces vibration
Maintenance-FreeNo lubrication required – reduces operating costs
Vibration DampingDiaphragm absorbs shock and dampens vibration – protects sensitive components
Lengthening DesignMore effectively compensates radial, angular, and axial deviations
Widely Used ApplicationsEncoders, servo motors, stepper motors, lead screws, instrumentation, small pumps
OEM CustomizationCustom bores, keyways, and materials available

Why Choose a Triple Diaphragm Coupling?

Triple diaphragm couplings offer the highest level of misalignment compensation among diaphragm coupling designs:

  • Zero Backlash: Essential for encoders, resolvers, and servo motors where accurate position feedback is required.

  • High Torsional Rigidity: Maintains system accuracy under load – precise torque transmission for servo control.

  • Superior Misalignment Compensation: Accommodates angular, radial (parallel), and axial misalignment with enhanced capability – reduces stress on bearings and seals.

  • Low Inertia: The lightweight aluminum design makes them ideal for high-speed operation and quick starts/stops.

  • Maintenance-Free: No lubrication required, reducing downtime and maintenance costs.

  • Fatigue Resistance: The 304 stainless steel diaphragm provides excellent fatigue resistance for long service life.

  • Lengthening Design: The lengthening design is adopted to more effectively compensate radial, angular and axial deviations.

Applications

  • Encoders & Resolvers – Precision position feedback systems

  • Servo Motors – High-precision motion control systems

  • Stepper Motors – Accurate positioning and step transmission

  • Lead Screws – Precision linear motion systems

  • Instrumentation – Precision measuring instruments

  • Small Pumps – Light-duty pump drives

  • Feed Rollers – Material handling and feeding systems

  • CNC Machines – Small CNC machines, engraving machines

  • Robotics – Small robot joint drives

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

Why Choose Apex Coupling for DW Series Diaphragm Couplings?

 
 
AdvantageDescription
Factory DirectCompetitive B2B pricing – no middlemen
Premium MaterialsAluminum alloy hubs + 304 stainless steel triple diaphragm
Zero BacklashPrecision performance for encoders, servo motors, and stepper motors
High Torsional RigidityAccurately controls shaft rotation – enables high-precision control
Superior Misalignment CompensationTriple diaphragm design accommodates angular, radial, and axial misalignment with enhanced capability
Low InertiaHigh-speed capability – up to 10000 RPM
Clamping Screw FasteningSecure, even clamping force – no shaft damage
H7 Precision BoreHigh concentricity and accurate shaft fit
Maintenance-FreeNo lubrication required – reduces operating costs
Wide Model RangeDW-19×34 to DW-82×128 – covers most applications
OEM CustomizationCustom bores, keyways, and materials available

FAQ

Q: What is a triple diaphragm coupling?
A: A triple diaphragm coupling consists of two aluminum hubs connected by three stainless steel diaphragms with center spacers. It transmits torque while compensating for angular, radial, and axial misalignment with zero backlash and high torsional rigidity.

Q: What is the advantage of the triple diaphragm design over double or single?
A: A triple diaphragm coupling provides enhanced misalignment compensation compared to single or double diaphragm designs – accommodating angular (2°), radial (0.55mm), and axial (±0.90mm) misalignment with maximum effectiveness.

Q: What materials are used?
A: The hubs are made of high-strength aluminum alloy. The diaphragms are made of 304 stainless steel – offering excellent fatigue resistance and corrosion resistance.

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

Q: What is the bore tolerance?
A: Standard bore tolerance is H7 for precision shaft fit and high concentricity.

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

Q: What are the common applications?
A: Encoders, resolvers, servo motors, stepper motors, lead screws, instrumentation, small pumps, and feed rollers.

Q: Can the coupling compensate for misalignment?
A: Yes. The triple diaphragm design compensates for angular (2°), radial (0.12-0.55mm), and axial (±0.20 to ±0.90mm) 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., DW-26×44.5-8K×9K).

Q: What is the maximum speed?
A: Maximum speed ranges from 8000 to 10000 RPM depending on the model.

Request a Quote

Send us your model (e.g., DW-26×44.5), bore size, torque, speed, and application details. Our engineers will recommend the optimal model and provide a quotation within 24 hours.

  • DW series coupling

  • Triple diaphragm coupling

  • Aluminum diaphragm coupling

  • Zero backlash coupling

  • Servo motor coupling

  • Stepper motor coupling

  • DW-19×34 DW-26×44.5 DW-34×58 DW-39×65.5 DW-44×65.5 DW-56×83 DW-68×97 DW-82×128

  • Flexible disc coupling

  • 304 stainless steel diaphragm

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DW series coupling

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