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Single/Double Diaphragm Coupling – 7075 Aluminum, 304 Stainless Steel Diaphragm, Zero Backlash for Servo/Stepper Motors
Model Number
Check below, custom
- Phone : +86 13431039760
- Wechat : +86 13431039760
- Whatsapp : +86 13431039760
- Email : ella@apexcoupling.com
Product Description
Single/Double Diaphragm Coupling – 7075 Aluminum, 304 Stainless Steel Diaphragm, Zero Backlash for Servo/Stepper Motors
Factory direct | 7075-T6 aircraft-grade aluminum | 304 stainless steel diaphragm | Zero backlash | 10000 N·m torque | 9000 RPM | H7 bore | 12.9 grade screws | Anodized finish | Single or double diaphragm | OEM custom
The Apexcoupling Diaphragm Coupling series is a precision metal flexible coupling engineered for high-performance power transmission in servo motor, stepper motor, and ball screw applications. Featuring zero rotational clearance, high torsional stiffness, and low moment of inertia, this coupling delivers exceptional positioning accuracy and dynamic response. Constructed from 7075-T6 aircraft-grade aluminum with 304 stainless steel diaphragm(s) and 12.9 grade high-strength screws, it offers outstanding corrosion resistance, durability, and reliability. Available in single diaphragm (compact, high torsional rigidity) and double diaphragm (compensates eccentricity) configurations.
✅ Zero backlash – ideal for servo and stepper motors. Smooth ball screw installation with no reaction force. High concentricity from 5-axis CNC machining.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Brand | Apexcoupling |
| Type | Flexible / Metal Diaphragm |
| Structure | Single diaphragm or double diaphragm |
| Hub Material | 7075-T6 aluminum alloy (aircraft-grade) |
| Diaphragm Material | 304 stainless steel – corrosion-resistant, oxidation-resistant, non-rusting |
| Surface Treatment | Anodized – natural color |
| Fastening Method | Screw fixing type – 12.9 grade black oxide screws |
| Max. Speed | 9000 RPM |
| Rated Torque | 10000 N·m |
| Allowable Eccentricity | 0.1 mm (double diaphragm) |
| Allowable Angular Misalignment | 1° |
| Allowable Axial Deviation | Yes |
| Bore Type | Round, through-hole |
| Bore Tolerance | H7 (100% inspected with H7 plug gauges) |
| Feature | Low moment of inertia (转动惯量低) |
| Backlash | Zero (no rotational clearance) |
| Maintenance | None required – lubrication-free |
| Customized support | OEM (non-standard customization available) |
| Applicable Industries | Servo motors, stepper motors, ball screws, CNC machines, automation equipment |
| Warranty | 1 Year |
| Place of Origin | Guangdong, China |
🔧 Custom bores, keyways, single/double diaphragm configuration, and special materials available. Contact us with your specifications.
Single Diaphragm vs Double Diaphragm – Which One Do You Need?
| Feature | Single Diaphragm | Double Diaphragm |
|---|---|---|
| Eccentricity compensation | ❌ Not allowed (structural limitation) | ✅ Yes – bends in different directions simultaneously |
| Angular misalignment | ✅ Yes | ✅ Yes |
| Axial deviation | ✅ Yes | ✅ Yes |
| Torsional rigidity | Higher | Moderate |
| Space requirement | Compact – saves space | Longer (requires intermediate spacer) |
| Best for | Space-constrained, high-rigidity applications | Applications requiring eccentricity compensation |
Selection guideline:
Choose single diaphragm when shafts are well-aligned and space is limited, or when maximum torsional rigidity is required.
Choose double diaphragm when eccentricity (parallel misalignment) is expected, as the double diaphragm can bend in different directions simultaneously to compensate for offset.
Product Features & Advantages
| Advantage | Benefit |
|---|---|
| 7075-T6 Aircraft-Grade Aluminum | High strength-to-weight ratio, excellent fatigue resistance, low moment of inertia – enables high-speed operation |
| 304 Stainless Steel Diaphragm | Corrosion-resistant, oxidation-resistant, non-rusting – long service life in harsh environments |
| Zero Backlash | No rotational clearance – precise positioning for servo and stepper motors |
| High Torsional Stiffness | Minimizes angular deflection under load – maintains system rigidity |
| Low Moment of Inertia | Faster acceleration/deceleration – improves dynamic response |
| H7 Bore Precision | High concentricity – reduces vibration and extends bearing life |
| 12.9 Grade Screws | High-strength, black oxide finish – secure fastening, no loosening under vibration |
| Anodized Surface | Enhanced corrosion resistance and wear resistance |
| R-Chamfered Slots | R-type rounded corners at slit positions – prevents stress concentration |
| Radius-Chamfered Screw Holes | Arc chamfering at socket head positions – prevents finger cuts during installation |
| 5-Axis CNC Machining | One-pass machining – ensures high concentricity and precision |
| Full Deburring | All machined edges chamfered – smooth, non-scratching surfaces |
| Maintenance-Free | No lubrication required – reduces operating costs |
| High Transmission Efficiency | Up to 99.86% – minimal power loss |
| Smooth Ball Screw Installation | No reaction force – ensures smooth, accurate linear motion |
Product Structure
Two 7075-T6 Aluminum Hubs – Aircraft-grade aluminum, precision-machined, anodized finish.
304 Stainless Steel Diaphragm(s) – Single or double diaphragm pack providing flexibility and misalignment compensation.
12.9 Grade High-Strength Screws – Black oxide finish for corrosion resistance and secure fastening.
Precision-Machined Features:
R-chamfered slots – R-type rounded corners at slit positions to avoid stress concentration
Radius-chamfered screw holes – Arc chamfering at socket head positions to prevent finger cuts
Full edge deburring – All machined positions chamfered – smooth, non-scratching
💡 The diaphragm coupling relies on the elastic deformation of the stainless steel diaphragm(s) to compensate for relative displacement between connected shafts. The single diaphragm provides high torsional rigidity in a compact package, while the double diaphragm allows for eccentricity compensation.
Applications
Servo Motors – High-precision motion control, zero backlash requirement
Stepper Motors – Accurate step transmission, no lost motion
Ball Screw Drives – Smooth, accurate linear positioning with no reaction force
CNC Machine Tools – Spindle drives, feed axes
Encoders – Precision position feedback
Robotics – Precise motion control
Automation Equipment – Pick-and-place, indexing tables
Semiconductor Equipment – High-precision positioning
Medical Devices – Precision motion systems
Printing Machinery – Register control, high-speed operation
Why Choose Apex Coupling for Diaphragm Couplings?
| Advantage | Description |
|---|---|
| Factory Direct | Competitive B2B pricing – no middlemen |
| Premium Materials | 7075-T6 aluminum + 304 stainless steel diaphragm – aircraft-grade quality |
| Zero Backlash | Precision performance for servo and stepper motors |
| High Torsional Stiffness | Maintains system rigidity under load |
| Low Inertia | Faster dynamic response – ideal for high-speed applications |
| H7 Precision Bore | 100% inspected with H7 plug gauges – high concentricity |
| 12.9 Grade Screws | High-strength, corrosion-resistant fastening |
| 5-Axis CNC Machining | One-pass precision – ensures concentricity and quality |
| Full Deburring | All edges chamfered – safe, smooth handling |
| OEM Customization | Custom bores, keyways, single/double configuration, and special materials available |
| Maintenance-Free | No lubrication required – reduces operating costs |
FAQ
Q: What is a diaphragm coupling?
A: A diaphragm coupling is a metal flexible coupling that uses one or more stainless steel diaphragms to transmit torque while compensating for misalignment. It relies on the elastic deformation of the diaphragm to accommodate angular, radial, and axial deviations.
Q: What is the difference between single and double diaphragm?
A: A single diaphragm coupling provides high torsional rigidity in a compact design but does not allow eccentricity (parallel misalignment). A double diaphragm coupling can compensate for eccentricity as well as angular and axial misalignment, as it can bend in different directions simultaneously.
Q: What does “zero backlash” mean?
A: Zero backlash means there is no rotational clearance between the hubs and the diaphragm. 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 7075-T6 aircraft-grade aluminum for high strength and low inertia. The diaphragm is made of 304 stainless steel for corrosion resistance and durability.
Q: What is the torque and speed rating?
A: Rated torque is 10000 N·m and maximum speed is 9000 RPM.
Q: What is the bore tolerance?
A: Standard bore tolerance is H7 – 100% inspected with H7 plug gauges for precision shaft fit.
Q: What grade are the screws?
A: The fastening screws are 12.9 grade high-strength alloy steel with black oxide finish.
Q: Is the coupling maintenance-free?
A: Yes. No lubrication required – reduces operating costs and maintenance schedules.
Q: What is the surface treatment?
A: The hubs are anodized (natural color) for enhanced corrosion resistance and wear resistance.
Q: Can I get a custom coupling?
A: Yes. We offer OEM customization – custom bores, keyways, single/double configuration, and special materials available.
Request a Quote
Send us your bore size, torque, speed, configuration (single/double diaphragm), and application details. Our engineers will recommend the optimal model and provide a quotation within 24 hours.
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