DLK7 Clamp Type Flexible Shaft Coupling is a zero-backlash one-piece metallic spring coupling designed for precise shaft connection in servo motors, stepper motors, ball screw drives, encoders and compact automation equipment. The clamp-type structure provides even shaft gripping force, helping improve concentricity and reduce shaft surface damage during installation.
Its flexible spring body can absorb small parallel, angular and axial misalignment while maintaining stable torque transmission in both clockwise and counterclockwise rotation. Aluminum alloy and stainless steel versions are available for different torque, rigidity, weight and working environment requirements.
Product Features
Zero Backlash Transmission
Suitable for motion systems that require accurate response between the driving shaft and driven shaft, such as servo drives, encoders and ball screw mechanisms.
Clamp Type Fastening
The clamp structure grips the shaft more evenly than point-contact set screws, which helps protect the shaft surface and improves assembly stability.
Misalignment Compensation
The one-piece spring structure absorbs small parallel, angular and shaft end-play errors, reducing stress on bearings, motors and connected components.
Aluminum or Stainless Steel
Aluminum alloy is suitable for lightweight and high-speed applications. Stainless steel is suitable for higher torque, stronger rigidity and better corrosion resistance.
Where DLK7 Clamp Couplings Are Used
DLK7 clamp type flexible couplings are commonly used between a motor shaft and a driven shaft where backlash, installation accuracy and compact structure matter. They are suitable for small automation mechanisms, measuring equipment, packaging machinery, CNC auxiliary axes, linear stages and transmission systems using ball screws, linear modules and precision rotary components.
| Application | Why DLK7 Is Suitable |
|---|---|
| Servo motor connection | Zero backlash and stable clockwise / counterclockwise transmission support accurate motion response. |
| Ball screw drive | Helps connect the motor shaft and screw end while absorbing small installation misalignment. |
| Encoder and measuring device | Low backlash and light structure help reduce transmission error in signal feedback systems. |
| Compact automation equipment | Small outer diameter options and clamp fastening make installation easier in limited space. |
Clamp Type vs. Set Screw Type
The main difference is the way the coupling locks onto the shaft. A clamp type coupling tightens around the shaft through a split clamping structure, while a set screw type coupling fixes the shaft by point contact. For servo transmission, frequent installation or shaft protection, clamp type is usually the better choice.
| Item | Clamp Type Coupling | Set Screw Type Coupling |
|---|---|---|
| Shaft fixing method | Even clamping around the shaft | Point locking by screw tip |
| Shaft surface protection | Better protection, less marking | May leave screw marks on the shaft |
| Concentricity after installation | More stable when installed correctly | More affected by screw tightening position |
| Recommended use | Servo, encoder, precision automation | Simple transmission and lower-cost applications |
Ordering Information
Please confirm the coupling material, outside diameter, d1 bore, d2 bore and whether a keyway is required before ordering. For example:
Example: DLK7-C40-1418
| Code | Meaning | Example |
|---|---|---|
| DLK7 | Series number | Clamp type flexible shaft coupling |
| C40 | Outside diameter D | 40 mm |
| 14 | d1 bore | 14 mm |
| 18 | d2 bore | 18 mm |
| K | Keyway customization suffix | DLK7-C40K-1418 |
If a keyway is required, it is manufactured as a non-standard customization. Please add the suffix K after the outside diameter in the model number, such as DLK7-C40K-1418.
Dimensions
The table below shows the main dimensions of DLK7 / DSK7 clamp type flexible shaft couplings. The bore options refer to available d1 and d2 combinations. Please confirm the actual motor shaft and driven shaft diameter before selecting the model.
| Model | Available Bore Options d1 / d2 (mm) | D (mm) | L (mm) | L1 (mm) | M | Tightening Torque (N·m) |
|---|---|---|---|---|---|---|
| DLK7-C12 / DSK7-C12 | 3, 4, 5 | 12 | 18.5 | 2.5 | M2 | 0.5 |
| DLK7-C16 / DSK7-C16 | 4, 5, 6, 6.35 | 16 | 23 | 3.25 | M2.5 | 1 |
| DLK7-C20 / DSK7-C20 | 5, 6, 8, 9.525 | 20 | 26 | 3.75 | M2.5 | 1 |
| DLK7-C25 / DSK7-C25 | 8, 9.525, 10, 11, 12 | 25 | 31 | 4.25 | M3 | 1.5 |
| DLK7-C32 / DSK7-C32 | 10, 11, 12, 14 | 32 | 41 | 6.0 | M4 | 2.5 |
| DLK7-C40 / DSK7-C40 | 10, 11, 12, 14, 15, 16, 18 | 40 | 56 | 8.5 | M5 | 4 |
| DLK7-C50 / DSK7-C50 | 12, 14, 15, 16, 18, 19 | 50 | 71 | 10.5 | M6 | 5 |
| DLK7-C63 / DSK7-C63 | 14, 15, 16, 18, 19, 24 | 63 | 90 | 13 | M8 | 16 |
Technical Specifications
When selecting a coupling, do not only check the bore size. Rated torque, maximum torque, rotational speed, torsional stiffness and allowable misalignment should also be considered. For continuous operation, the selected model should have enough torque margin instead of working near the maximum torque limit.
| Model | Rated Torque (N·m) | Max. Torque (N·m) | Max. Speed (r/min) | Moment of Inertia | Static Torsion Stiffness | Eccentricity Error (mm) | Angular Error | Shaft End-play Error (mm) | Mass (g) |
|---|---|---|---|---|---|---|---|---|---|
| DLK7-C12 | 0.5 | 1 | 10000 | 7.6 × 10-8 | 34 | 0.1 | 1.5 | ±0.3 | 4 |
| DLK7-C16 | 0.8 | 1.6 | 9300 | 3.2 × 10-7 | 46 | 0.1 | 1.5 | ±0.3 | 8 |
| DLK7-C20 | 1.1 | 2.2 | 7500 | 8.8 × 10-6 | 118 | 0.1 | 1.5 | ±0.3 | 18 |
| DLK7-C25 | 1.4 | 2.8 | 6000 | 2.5 × 10-6 | 167 | 0.15 | 1.5 | ±0.35 | 32 |
| DLK7-C32 | 2.8 | 5.6 | 4600 | 9.6 × 10-6 | 228 | 0.15 | 1.5 | ±0.35 | 66 |
| DLK7-C40 | 6.3 | 12.6 | 3600 | 3.2 × 10-5 | 346 | 0.2 | 1.5 | ±0.35 | 138 |
| DLK7-C50 | 11 | 22 | 3000 | 9 × 10-5 | 580 | 0.2 | 1.5 | ±0.35 | 272 |
| DLK7-C63 | 22 | 44 | 2200 | 3.1 × 10-4 | 843 | 0.2 | 1.5 | ±0.35 | 530 |
| DSK7-C12 | 0.8 | 1.6 | 10000 | 2.1 × 10-7 | 62 | 0.1 | 1.5 | ±0.3 | 14 |
| DSK7-C16 | 1.1 | 2.2 | 9300 | 8.9 × 10-7 | 83 | 0.1 | 1.5 | ±0.3 | 26 |
| DSK7-C20 | 1.6 | 3.2 | 7500 | 2.4 × 10-6 | 246 | 0.1 | 1.5 | ±0.3 | 48 |
| DSK7-C25 | 2.2 | 4.4 | 6000 | 7.0 × 10-6 | 315 | 0.15 | 1.5 | ±0.35 | 78 |
| DSK7-C32 | 5.5 | 11 | 4600 | 2.6 × 10-5 | 845 | 0.15 | 1.5 | ±0.35 | 174 |
| DSK7-C40 | 8.7 | 17.4 | 3600 | 8.9 × 10-5 | 990 | 0.2 | 1.5 | ±0.35 | 372 |
| DSK7-C50 | 16 | 32 | 3000 | 2.7 × 10-4 | 1380 | 0.2 | 1.5 | ±0.35 | 760 |
| DSK7-C63 | 38 | 76 | 2200 | 8.7 × 10-4 | 1790 | 0.2 | 1.5 | ±0.35 | 1410 |
Note: Moment of inertia and mass values are calculated with the maximum allowable bore size.
How to Select the Right Coupling
1. Confirm the shaft diameters. Check the motor shaft diameter and driven shaft diameter, then select the correct d1 and d2 bore combination.
2. Check torque margin. The rated torque should be higher than the normal working torque of the system. Do not use maximum torque as the continuous working value.
3. Match the material. Choose aluminum alloy for lightweight and high-speed applications. Choose stainless steel when higher rigidity, torque capacity or corrosion resistance is required.
4. Control installation misalignment. Flexible couplings can absorb small errors, but they are not a substitute for proper shaft alignment.
5. Confirm customization requirements. If keyway, special bore size or other non-standard processing is required, please provide a drawing or detailed shaft information.
FAQ
Q: What is the advantage of a clamp type flexible coupling?
A: A clamp type coupling locks the shaft with more uniform force. It is easier to install and remove, and it helps reduce shaft surface damage compared with point-contact set screws.
Q: Can DLK7 couplings compensate for shaft misalignment?
A: Yes. The spring slit structure can absorb small parallel, angular and axial errors. However, proper motor and shaft alignment is still required for stable operation and longer service life.
Q: How should I choose between aluminum alloy and stainless steel?
A: Aluminum alloy is suitable for lightweight and high-speed applications. Stainless steel is better when higher torque, stronger rigidity or better corrosion resistance is required.
Q: Can DLY make a keyway or special bore size?
A: Yes. Keyway and special bore requirements can be customized. Please provide the required bore size, keyway details and application information for confirmation.
Need Help Selecting a Flexible Shaft Coupling?
Send us your motor shaft diameter, driven shaft diameter, required torque, speed and application environment. DLY can help confirm the suitable DLK7 coupling model and customization requirements.
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