DIN 981 Slotted Round Locknut | KM Series Bearing Lock Nut for Shafts

• Standard Compliance: Fully compliant with DIN 981:2009 and ISO 2982 standards for universal compatibility.
• Precision Runout Control: Controlled axial runout accuracy to ensure stable bearing performance and extended service life.
• Secure Locking Mechanism: Designed with 4 to 8 slots for perfect engagement with DIN 5406 (MB) lockwashers.
• High Strength Material: Made from Property Class 14H steel or AISI 304 stainless steel for high axial load capacity.
• Versatile Surface Finishing: Available in black oxide, zinc plating, or plain finish to suit different environmental requirements.

• Material Integrity: Manufactured from Property Class 14H Carbon Steel or AISI 304/316 Stainless Steel.
• Thread Precision: All threads are machined to ISO 965-2 6g tolerances to ensure maximum stripping resistance and smooth assembly.
• Surface Finish Options: Optimized for corrosion resistance with Black Oxide (Phosphating), Zinc Plating (Cr3+), or Plain Finish with anti-rust oil.
• Precision Face Runout: Yokelink strictly controls the perpendicularity between the bearing face and the thread axis to prevent shaft misalignment.
• Chamfered Design: According to DIN 981, a 30° chamfer is applied to facilitate easy installation and better engagement with the lockwasher.

Yokelink DIN 981 Bearing Locknuts Specification:

Technical Notes

DIN 981 Bearing Lock Nuts Applications:

DIN 981 bearing lock nuts are widely applied in mechanical systems requiring reliable anti-loosening for rolling bearings. In the automotive field, they fix wheel hubs and engine components, withstanding vibrations from road conditions to ensure safety. For agricultural machinery operating in harsh environments. In Construction machinery like excavators and tower cranes, they suit high-vibration scenarios. The power industry uses them in wind turbines to fix bearings against long-term wind-induced vibrations.

 

 

 

The most secure design is no good when the screw joint breaks down later. Precise analysis of prevailing types of load and properties is therefore very important. This will decide whether locknuts compliant with DIN 981, 6923, 6927 or a self-locking slotted nut with a polyamide ring will ensure the right connection.

 

Frequently Asked Questions (FAQ)

 

1. What is a DIN 981 Locknut used for?

A: A DIN 981 locknut, commonly known as a KM or slotted round nut, is specifically designed for the axial securing of rolling bearings on shafts or adapter sleeves. Its primary function is to provide a reliable clamping force to prevent bearing displacement during high-speed rotation or vibration.

2. What are the material requirements for DIN 981 nuts?

A: According to the standard, these locknuts must be manufactured from steel with a minimum property class of 14H. This ensures a hardness range of 140 HV to 215 HV. Yokelink also offers stainless steel versions (AISI 304/316) for applications requiring high corrosion resistance.

3. Which locking mechanism is required for DIN 981 KM nuts?

A: DIN 981 nuts are "non-self-locking" and must be used in conjunction with a DIN 5406 lockwasher (MB series). The washer's inner tab fits into the shaft keyway, while one of its outer tabs is bent into a slot on the nut's circumference to provide a positive mechanical lock.

4. What thread tolerances are standard for KM locknuts?

A: The threads are metric fine pitch and must adhere to the 6g tolerance class according to ISO 965. This precision ensures smooth assembly and maximum stripping resistance under axial loads.

5. How many slots do DIN 981 locknuts have?

A: The number of slots depends on the size of the nut. Smaller sizes (up to KM 10) typically feature 4 slots, while larger sizes (from M45x1.5 or KM 11 and above) usually have 6 or 8 slots to facilitate easier tightening and locking.

6. What is the recommended surface treatment for these nuts?

A: Standard industrial finish includes black oxide (phosphating) or zinc plating (galvanized) to protect against rust. For precision applications, the contact surface (bearing face) is often ground to improve axial runout accuracy.

7. Can a DIN 981 nut be used on a shaft without a keyway?

A: No, a standard DIN 981/DIN 5406 assembly requires a keyway on the shaft thread for the washer's inner tab. For shafts without keyways, Yokelink recommends using self-locking series such as GUK (with nylon insert) or KMT (with locking pins).

8. What does the size code (e.g., KM 10) represent?

A: The numeric code represents the size of the compatible shaft or bearing bore. For example, KM 10 corresponds to an M50 x 1.5 thread, while KM 20 corresponds to an M100 x 2 thread.

9. What are the temperature limits for DIN 981 locknuts?

A: All-metal steel or stainless steel DIN 981 nuts can operate in high-temperature environments (up to 300°C depending on the lubricant). However, if using a self-locking variant like the GUK series, the temperature is limited to 100°C due to the Polyamide insert.

10. How to calculate the tightening torque for a KM nut?

A: Tightening torque depends on the required axial preload for the specific bearing. Engineers should refer to the permissible axial load ($F_A$) specified in the Yokelink catalog to ensure the nut can withstand the operational forces.