DLY DLK7 / DSK7 one-piece metallic spring coupling is a setscrew type flexible shaft coupling designed for compact precision transmission systems. The one-piece metallic spring body helps provide zero backlash transmission while absorbing parallel misalignment, angular misalignment and shaft end-play through its flexible spring structure.
This coupling is commonly used between motors and driven components such as servo motors, stepper motors, ball screws, encoders, CNC equipment and automation devices. DLK7 is suitable for applications requiring lightweight aluminum alloy coupling, while DSK7 is available for applications requiring stainless steel material and higher rigidity.
Selection Tip: When selecting this setscrew type flexible coupling, confirm the shaft diameter on both sides, required torque, maximum speed, allowable misalignment and working environment. For applications requiring stronger shaft clamping force, a clamp type coupling may be more suitable.
Product Features
Zero Backlash Transmission
The one-piece metallic spring structure supports accurate torque transmission without an elastic insert, helping reduce lost motion in precision positioning systems.
Misalignment Compensation
The flexible body can absorb parallel misalignment, angular misalignment and shaft end-play, helping protect connected shafts and bearings.
Setscrew Fixing Structure
The setscrew structure is compact and easy to install, making it suitable for small motors, encoders and light to medium precision transmission systems.
Material Options
Aluminum alloy and stainless steel versions are available for different requirements in weight, rigidity, torque capacity and working environment.
Ordering Information
The model code usually includes the coupling series, size, bore diameter on both sides and optional customization. Please confirm the shaft diameters of the driving side and driven side before ordering.
| Model Section | Meaning | Example |
|---|---|---|
| DLK7 / DSK7 | One-piece metallic spring coupling series | DLK7 |
| C20 | Coupling size group / outer diameter 20 mm | C20 |
| 06 | d1 bore diameter, 6 mm | 06 |
| 08 | d2 bore diameter, 8 mm | 08 |
| K | Optional keyway customization | DLK7-C20K-0608 |
Model example: DLK7-C20-0608 means DLK7 series coupling, C20 size, 6 mm bore on one side and 8 mm bore on the other side. If a keyway is required, please add "K" after the outer diameter code and confirm it as a non-standard customization.
DLK7 / DSK7 Coupling Dimensions
The following dimensional table helps confirm coupling size, available bore diameters, overall length, set screw specification and recommended wrench torque. Unit: mm unless otherwise stated.
| Size Group | Available Bore Sizes d1 / d2 | D | L | L1 | Set Screw M | Wrench Torque N·m |
|---|---|---|---|---|---|---|
| DLK7-C12 / DSK7-C12 | 3 / 4 / 5 | 12 | 18.5 | 2.5 | M2.5 | 0.5 |
| DLK7-C16 / DSK7-C16 | DLK7: 4 / 5 DSK7: 6 / 6.35 |
16 | 23 | 3 | M3 | 0.7 |
| DLK7-C20 / DSK7-C20 | DLK7: 5 / 6 DSK7: 8 / 9.525 |
20 | 26 | 3 | M3 | 0.7 |
| DLK7-C25 / DSK7-C25 | DLK7: 8 / 9.525 DSK7: 10 / 11 / 12 |
25 | 31 | 4.25 | M3 | 1.5 |
| DLK7-C32 / DSK7-C32 | DLK7: 10 / 11 DSK7: 12 / 14 |
32 | 41 | 6.00 | M4 | 2.5 |
| DLK7-C40 / DSK7-C40 | DLK7: 10 / 11 / 12 / 14 DSK7: 15 / 16 / 18 |
40 | 56 | 8.5 | M5 | 4 |
| DLK7-C50 / DSK7-C50 | DLK7: 12 / 14 / 15 DSK7: 16 / 18 / 19 |
50 | 71 | 10.5 | M6 | 8 |
| DLK7-C63 / DSK7-C63 | DLK7: 14 / 15 / 16 DSK7: 18 / 19 / 24 |
63 | 90 | 13 | M8 | 16 |
Technical Specifications
The following technical specifications help compare rated torque, maximum torque, rotational speed, stiffness, allowable misalignment and mass. Moment of inertia and mass values are calculated with the maximum allowable bore size.
| Type | Rated Torque N·m | Max. Torque N·m | Max. Speed r/min | Moment of Inertia | Static Torsion Stiffness | Parallel Misalignment mm | Angular Misalignment | Shaft End-play mm | Mass g |
|---|---|---|---|---|---|---|---|---|---|
| DLK7-C12 | 0.5 | 1 | 30000 | 8.2 × 10⁻⁸ | 33 | 0.1 | 1.5 | ±0.3 | 4 |
| DLK7-C16 | 0.8 | 1.6 | 22000 | 3.2 × 10-7 | 46 | 0.1 | 1.5 | ±0.3 | 8 |
| DLK7-C20 | 1.1 | 2.2 | 18000 | 8.8 × 10-6 | 118 | 0.1 | 1.5 | ±0.3 | 16 |
| DLK7-C25 | 1.4 | 2.8 | 14000 | 2.5 × 10-6 | 165 | 0.15 | 1.5 | ±0.35 | 28 |
| DLK7-C32 | 2.8 | 5.6 | 10000 | 9.5 × 10⁻⁶ | 270 | 0.15 | 1.5 | ±0.35 | 62 |
| DLK7-C40 | 6.3 | 12.6 | 9400 | 3.1 × 10⁻⁵ | 345
|
0.2 | 1.5 | ±0.35 | 135 |
| DLK7-C50 | 11 | 22 | 7600 | 1.0 × 10⁻⁵ | 580 | 0.2 | 1.5 | ±0.35 | 266 |
| DLK7-C63 | 22 | 44 | 6000 | 3.0 × 10⁻⁴ | 830 | 0.2 | 1.5 | ±0.35 | 500 |
| DSK7-C12 | 0.8 | 1.6 | 30000 | 2.0 × 10⁻⁷
|
60 | 0.1 | 1.5 | ±0.3 | 12 |
| DSK7-C16 | 1.1 | 2.2 | 22000 | 8.3 × 10⁻⁷ | 80 | 0.1 | 1.5 | ±0.3 | 22 |
| DSK7-C20 | 1.6 | 3.2 | 18000 | 2.2 × 10⁻⁶ | 235 | 0.1 | 1.5 | ±0.3 | 40 |
| DSK7-C25 | 2.2 | 4.4 | 14000 | 6.7 × 10⁻⁶ | 315 | 0.15 | 1.5 | ±0.35 | 74 |
| DSK7-C32 | 5.5 | 11 | 10000 | 2.5 × 10⁻⁵ | 837 | 0.15 | 1.5 | ±0.35 | 162 |
| DSK7-C40 | 8.7 | 17.4 | 9400 | 8.6 × 10⁻⁵ | 980
|
0.2 | 1.5 | ±0.35 | 354 |
| DSK7-C50 | 16 | 32 | 7600 | 2.6 × 10⁻⁴ | 1385 | 0.2 | 1.5 | ±0.35 | 710 |
| DSK7-C63 | 38 | 76 | 6000 | 8.2 × 10⁻⁴
|
1795 | 0.2 | 1.5 | ±0.35 | 1310 |
How to Select a Setscrew Type Flexible Coupling
1. Confirm shaft diameters: Check d1 and d2 bore sizes on the motor side and driven side.
2. Check torque: Select a coupling with rated torque higher than the actual working torque. Consider acceleration, deceleration and load changes.
3. Check speed: Make sure the maximum rotational speed meets the machine operating speed.
4. Check alignment: Keep shaft alignment within the allowable parallel, angular and axial compensation range.
5. Choose material: Aluminum alloy is suitable for lightweight and low inertia applications. Stainless steel is suitable for higher rigidity, higher torque and more demanding environments.
Typical Applications
Frequently Asked Questions
Q: What is the difference between setscrew type and clamp type coupling?
A: A setscrew type coupling fixes the shaft by screws pressing against the shaft surface. It is compact and easy to install. A clamp type coupling grips the shaft more evenly and is usually preferred when stronger holding force or better concentricity is required.
Q: Can this coupling compensate shaft misalignment?
A: Yes. The one-piece metallic spring structure can compensate for limited parallel misalignment, angular misalignment and shaft end-play. However, correct shaft alignment is still important for stable operation and longer service life.
Q: Is this coupling suitable for ball screw transmission?
A: Yes. It can be used between a motor and a ball screw in light to medium precision transmission systems. The rated torque, shaft diameter and maximum speed should be checked before selection.
Q: Can DLY provide customized bore sizes or keyway processing?
A: Standard bore sizes are listed in the dimension table. Keyway options and special bore requirements can be confirmed as non-standard customization before ordering.
Need Help Selecting a Flexible Shaft Coupling?
Send us your motor shaft diameter, driven shaft diameter, torque, speed and working environment. DLY can help confirm a suitable DLK7 / DSK7 coupling model for your application.
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