Flender ZAPEX ZNN 280 Heavy-Duty Gear Coupling
The Flender ZAPEX ZNN 280 is a heavy-duty double-gimbal curved-tooth gear coupling engineered for ultra-high torque transmission in compact industrial drivetrains. Featuring precision-machined crowned teeth, the ZAPEX ZNN 280 delivers a nominal torque rating of 62,000 Nm (peak capacity up to 140,000 Nm) while accommodating angular, parallel, and axial shaft misalignments with minimal restoring forces. Covering 20 frame sizes from size 83 to 1000 (1,020 Nm to 7,200,000 Nm), ZAPEX couplings feature standard double-engagement designs (ZNN), extended axial float units (ZNA), single-engagement cardan drives (ZNNA), attached brake discs (ZWB/ZNNB), high-speed steel designs (ZWS), and vertical executions (ZWNV). They are heavily specified in steel rolling mills, continuous casting lines, crane hoists, cement kilns, marine propulsion, and mining winches.
Technical Specifications
| Model / Part Number | ZAPEX ZNN 280 (Type ZNN, Size 280 Double-Engagement) |
|---|---|
| Brand / Manufacturer | Flender GmbH |
| Structural Execution | Type ZNN (Standard double-engagement all-steel gear coupling) |
| Nominal Torque Output | 62,000 Nm (Size 280) / 1,020 Nm to 7,200,000 Nm (Full Series Range) |
| Misalignment Capability | Angular misalignment up to ±1.5° per gearing half |
| Lubrication & Seals | High-performance synthetic grease / oil with DUO double radial shaft seals |
| ATEX Certification | Certified according to 2014/34/EU Directive for explosive atmospheres (Zone 1/21 & 2/22) |
| Construction Material | High-tensile forged alloy steel sleeve and crowned tooth hubs |
Documentation & Resources
Flender ZAPEX Series Modular Architecture Matrix
Full-range structural configuration guide for Flender ZAPEX heavy-duty curved-tooth gear couplings. Review supported execution types, brake disc attachments, high-speed steel designs, and vertical layouts:
| Coupling Type & Structural Execution | Frame Sizes Covered | Nominal Torque Rating (Nm) | Key Operational Advantages & Applications |
|---|---|---|---|
| ZAPEX Type ZNN (Standard Double-Engagement) | Size 83 to Size 1000 (20 Sizes) | 1,020 Nm - 7,200,000 Nm | Universal High Torque (Mill stands & heavy drives) |
| ZAPEX Type ZNA (Extended Shaft Distance) | Size 83 to Size 800 (18 Sizes) | 1,020 Nm - 3,500,000 Nm | Extended DBSE (Accommodates large shaft spacing) |
| ZAPEX Type ZWB / ZNNB (With Brake Disc) | Size 107 to Size 530 (13 Sizes) | 2,000 Nm - 350,000 Nm | Brake Integration (Heavy crane hoist & winch brakes) |
| ZAPEX Type ZWS / ZWNV (High Speed & Vertical) | Size 83 to Size 530 (14 Sizes) | 1,020 Nm - 350,000 Nm | High Speed / Vertical (Pump shafts & turbomachinery) |
| ZAPEX Type ZND / ZNH (Intermediate Spacers) | Size 107 to Size 400 (10 Sizes) | 2,000 Nm - 160,000 Nm | Spacer Sleeves (Eases motor / pump disassembly) |
Legacy Gear Coupling Replacement & ZAPEX Upgrade Guide
Worn toothed gear couplings installed on rolling mills, cement kilns, and crane hoists can be directly replaced with Flender ZAPEX high-capacity couplings. Refer to the replacement mapping below for 1-to-1 retrofitting:
| Legacy Coupling Series / Type | Coupling Mechanism | Current ZAPEX Equivalent Model | Torque Capacity | Mechanical Fit & Retrofit Engineering Notes |
|---|---|---|---|---|
| Legacy ZAPEX Size 280 Type ZNN | Curved Gear Tooth | ZAPEX Type ZNN 280 Current Standard | 62,000 Nm | Direct 1-to-1 flange bolt circle & gear tooth pitch match. |
| Conventional Straight Gear Couplings | Straight Spur Gearing | ZAPEX Type ZNN 210 / 240 / 280 Crowned Tooth | 28,000 Nm - 62,000 Nm | Crowned tooth profile eliminates edge pressure and extends life. |
| Steel Mill Roll Stand Drives | High Torque Gear Sleeve | ZAPEX Type ZNN 280 / 320 / 360 Mill Duty | 62,000 Nm - 140,000 Nm | Transmits extreme reversing impact loads in rolling mills. |
| Heavy Crane Hoist Winch Drives | Gear Coupling with Brake | ZAPEX Type ZWB / ZNNB 280 + Brake Brake Disc | 62,000 Nm | Forged steel hub with integrated caliper brake disc. |
| Vertical Pump & Mixer Shafts | Standard Horizontal Gear | ZAPEX Type ZWNV 280 Vertical Vertical Duty | 62,000 Nm | Special DUO oil retention seals prevent lubricant leakage. |
Expert Selection & Retrofit Engineering Notes
When servicing existing installations featuring worn gear teeth or leaking seals, we stock genuine Flender ZAPEX crowned tooth hubs, flanged sleeves, and DUO double radial seal kits. Simply supply us with your coupling size, bore diameters, distance between shaft ends (DBSE), and operating torque, and our engineering team will deliver a 100% compliant replacement specification and proposal.
Core Benchmark Model Standard Configurations
- ZAPEX Type ZNN 130
- ZAPEX Type ZNN 180
- ZAPEX Type ZNN 210
- ZAPEX Type ZNN 240
- ZAPEX Type ZNN 280
- ZAPEX Type ZNN 320
- ZAPEX Type ZNN 360
- ZAPEX Type ZNN 400
- ZAPEX Type ZNN 480
- ZAPEX Type ZNA 280 (Long DBSE)
- ZAPEX Type ZNNA 280 (Single Eng.)
- ZAPEX Type ZWB 280 (Brake Disc)
- ZAPEX Type ZWS 280 (High Speed)
- ZAPEX Type ZWNV 280 (Vertical)
- ZAPEX Type ZND 280 (Spacer)
- ZAPEX Crowned Hub Size 280
- ZAPEX Flanged Sleeve Size 280
- ZAPEX DUO Seal Kit Size 280
- ZAPEX O-Ring Kit Size 280
- Flender High-Load Gear Grease
