THK BK25 Ball Screw Support Bearing Unit BK25

Description:

The THK BK25 Ball Screw Support Bearing Unit is a fixed-side support unit designed for 25 mm ball screw shafts, incorporating factory-preloaded angular contact bearings for precise axial positioning and high-rigidity support. Commonly installed in CNC machine tools, industrial automation systems, semiconductor equipment, packaging machinery, robotics, and precision manufacturing equipment utilizing ball screw drive systems. Machine builders, maintenance technicians, and system integrators use this support unit for new machine construction, retrofits, repairs, and replacement of fixed-end ball screw bearing assemblies.

Applications:

The THK BK25 belongs to THK's standardized BK Series fixed-side support units for ball screw assemblies. It features a rigid cast housing with preloaded JIS Class 5 angular contact bearings to eliminate axial play while maintaining excellent rotational accuracy and stiffness. Designed to work with compatible BF25 floating-side support units, the BK25 provides accurate shaft alignment, high load capacity, and long service life in demanding linear motion applications. It is widely used in CNC machining centers, automated assembly systems, precision inspection equipment, and factory automation where reliable ball screw support is essential.

Technical Specifications:

• Brand: THK
• Part Number: BK25
• Reference Number: 131217
• Product Type: Fixed-Side Ball Screw Support Bearing Unit
• Series: BK Support Unit Series
• Ball Screw Shaft Diameter: 25 mm
• Housing Type: Square Fixed-Side Support Unit
• Bearing Type: Factory-Preloaded Angular Contact Bearings
• Bearing Accuracy: JIS Class 5
• Shaft Thread Compatibility: M25 × 1.5
• Housing Height (H): 80 mm
• Housing Width (B): 106 mm
• Housing Length (L): 42 mm
• Shaft Bore: 25 mm
• Housing Material: High-Strength Steel/Cast Steel
• Mounting Style: Fixed-End Flange Mount
• Compatible Floating Support Unit: THK BF25
• Compatible Ball Screw Series: THK Precision and Rolled Ball Screws with BK25 shaft-end machining
• Features: Factory-preloaded bearings, high axial rigidity, low runout, precision alignment, maintenance-free operation, compact standardized design, high-speed capability.

Common Replacements:

• THK BK20
• THK BK30
• THK FK30