Type B Leaf Spring Nut

Product introduction

The B-type leaf spring nut is a fastening nut that combines an elastic leaf spring with a threaded body. It adopts a "U"-shaped or "bow"-shaped leaf spring structure. It can be quickly snapped into the sheet metal edge or square hole during installation to achieve unilateral operation and elastic self-locking. As an important auto parts nut, it is widely used in body sheet metal, door modules, bumper brackets, car light fixing and other positions to effectively prevent vibration loosening.

The products cover special-shaped nuts and non-standard nuts. The structure can be customized according to the workpiece plate thickness, installation interface and load requirements, and can be flexibly adapted to different assembly scenarios. Our company has passed IATF 16949 quality system certification, provides full-process services from sample development to batch delivery, and provides customers with fastening solutions with high reliability and high assembly efficiency.

 

Product design and features

The B-type leaf spring nut is a fastening nut that combines a nut body with an elastic leaf spring structure. Its typical feature is the combined design of a "U"-shaped or "bow"-shaped leaf spring and a threaded body. During installation, the leaf spring arm generates elastic clamping force, allowing the nut to be firmly clamped on the edge of the workpiece or square hole, achieving rapid positioning and self-locking.

 

Main design features:

Elastic clamping structure: The leaf spring arm provides continuous elastic pressing force, effectively eliminating thread gaps and preventing loosening due to vibration.

Quick installation: No need for welding or riveting, it can be directly inserted into the edge of sheet metal or pre-made holes, greatly improving assembly efficiency

Two-way limit design: The leaf spring structure achieves axial and circumferential positioning at the same time and is not easy to rotate after installation.

Detachability: supports multiple disassembly and assembly for easy maintenance and replacement

 

Materials and application areas

Material:

Leaf spring material: high-quality spring steel (65Mn, SUS301, etc.), with stable elasticity and excellent fatigue life after heat treatment

Nut material: carbon steel, stainless steel or copper alloy, meeting different strength and corrosion resistance requirements

Surface treatment: Dacromet, galvanizing, nickel plating, phosphating, etc., adapt to different environmental anti-corrosion levels

 

Application areas:

B-type leaf spring nuts are widely used in industries that require quick assembly + anti-vibration and anti-loosening:

Automobile manufacturing: As important auto parts nuts, they are widely used in body sheet metal edges, door modules, bumper brackets, headlight fixings, seat slide rails, etc., to meet the dual needs of the automotive industry for assembly efficiency and connection reliability.

Rail transit: used for fixing interior panels and electrical cabinets in carriages

Engineering machinery: suitable for connecting covering parts with severe vibration

Power electrical: used for rapid installation of internal components of power distribution cabinets and control cabinets

 

Quality control and certification system

The B-type leaf spring nut is a key fastening nut, especially when used in automotive parts nut scenarios. Its quality is directly related to the safety and reliability of the entire vehicle. Our company has established a full-process quality control system:

Raw material control: 100% batch re-inspection of spring steel strips to ensure that hardness, elastic modulus, and thickness tolerances meet requirements

 

Process control:

Stamping Forming: Critical Dimensions Monitored with SPC (Statistical Process Control)

Heat treatment: continuous furnace production, real-time recording of temperature curve and hardness distribution

Surface treatment: salt spray test, hydrogen embrittlement test, coating adhesion test

Finished product testing: elastic clamping force test, torque-clamping force test, vibration and anti-loosening test (according to GB/T 10431 or ISO 16130 standard) fatigue life test

 

Certification system:

ISO 9001, IATF 16949 (automotive industry quality management system)

Products meet RoHS and REACH environmental protection requirements

PPAP (Production Part Approval Process) level three document package available

For nuts with special shapes and non-standard nuts, we have established a special quality control process to ensure that each customized product maintains a process capability index Cpk ≥ 1.33 while increasing the structural complexity.

 

Customized services

Structural customization: According to the edge shape or opening form of the customer's workpiece, design the length, width, and bending angle of the leaf spring arm, adjust the elastic clamping force, match different plate thicknesses (0.8mm – 5.0mm) and load requirements, and add error-proof structures, guide structures, and positioning bumps

Size and thread customization: Thread specifications: metric, imperial, American and non-standard threads (mainly M3 – M12) Installation dimensions: adapted to different edge widths, opening sizes, outlines: symmetrical, offset, widened, etc.

Functional integration: Integrate the fastening nut with the line card, bracket and sealing ring to reduce the types of parts and provide pre-glued anti-loosening and anti-leakage sealing functions.

 

FAQ

Q: What are the advantages of B-type leaf spring nuts compared with ordinary welding nuts?

A: B-type leaf spring nuts belong to the "elastic clamping type" among fastening nuts. They do not require welding equipment and processes and can be directly clamped into the workpiece. They are especially suitable for painted or plated workpieces. They will not damage the surface anti-corrosion layer and are easy to disassemble and repair.

 

Q: In the automotive field, where are B-type leaf spring nuts mainly used? Are they standard auto parts nuts?

A: Yes, B-type leaf spring nuts are typical automotive parts nuts and are widely used in body sheet metal edges, door inner panels, bumper brackets, lamp holders, seat structures, etc. Its anti-vibration performance meets the higher-level anti-loosening requirements of the automotive industry.

 

Q: How to ensure that the special-shaped leaf spring nut does not loosen in a vibration environment?

A: We adopt the dual anti-loosening mechanism of "leaf spring elastic clamping force + thread fit". For non-standard nuts, the leaf spring force value will be optimized through finite element analysis, and vibration tests will be conducted on samples to verify to ensure that the clamping force attenuation is within the allowable range.

 

Q: Will the elastic clamping force of the leaf spring nut decay with time?

A: High-quality spring steel has good stress relaxation resistance after reasonable heat treatment. We have verified through fatigue life testing that under rated working load, the elastic attenuation is controlled within the allowable range and meets long-term use requirements.

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