Application NotesTechnical Documentation & Guides

Overview

An NB ball spline moves linearly along a splined shaft while carrying torque, so you get travel and rotation on one shaft. Where a conventional spline slides, this one runs on recirculating balls: low friction, zero backlash, long life. Sizing it comes down to matching load capacity, stroke, and torque to the right model.

Load Capacity Calculations

Start with the loads on the spline. You need the radial load (perpendicular to the shaft), the moment load (torque about the shaft), and any combined loading:

• Basic dynamic load rating (C) for continuous motion applications
• Basic static load rating (Co) for stationary or slow-speed loads
• Calculate equivalent load: Pe = Fr + 0.5 × Mt/dp (radial + moment)
• Service life: L = (C/Pe)³ × 50 km (basic rating life)
• Apply service factor for shock, vibration, and environmental conditions

Spline Shaft and Nut Selection

NB ball spline shafts run from 6mm to 50mm diameter. Size the shaft from your load numbers, then pick the nut to suit the mounting: flange, block, or cylindrical. High-torque jobs want more ball circuits (3 or 6) for the extra torque capacity.

Installation Considerations

Alignment between the shaft and its mating parts drives ball spline performance. Get it wrong and the balls load unevenly, which cuts life and adds friction. Mount to precision ground surfaces and check alignment with a dial indicator as you install. Grease it with the specified lubricant before the first run.

Typical Applications

• Robotic tool changers
• Pick-and-place with rotation
• Screw driving systems
• Vertical transfer with rotation

Related Products

SSP Series • SBS Series • SSS Series

Overview

NB linear guides run on recirculating balls or rollers, so the motion stays smooth and rigid. Sizes go from miniature up to heavy-duty, with accuracy grades from standard (±20µm) down to ultra-precision (±2µm). Sizing one means running the load numbers, picking an accuracy grade, and matching the guide to its environment.

Load Analysis and Rail Sizing

Start with the loads on each carriage block: dead weight, cutting forces, acceleration forces, and moment loads. NB rates its guides for radial, reverse radial, and lateral loading:

• Radial load capacity (downward, into the rail)
• Reverse radial capacity (upward, away from the rail)
• Lateral load capacity (side loads)
• Moment load capacity (pitch, yaw, and roll)
• Calculate equivalent load considering all directions

Accuracy Grade Selection

NB linear guides come in several accuracy grades. A higher grade holds tighter running parallelism and less height variation between carriages, which matters when the work is precision. Standard grade covers general automation. Measurement, optics, and semiconductor work need the precision and ultra-precision grades.

Sealing and Environment

For dusty, wet, or corrosive conditions, NB has stainless steel guides plus seals and scrapers. End seals keep contamination out of the ball recirculation path; bottom seals keep debris off the rail surface. Cleanroom work can use the low-particle-generation seals and greases.

Typical Applications

• Machine tool axes
• Semiconductor handling
• Metrology and inspection
• Medical device mechanisms

Related Products

SGL Series • SER Series • SEB Series

Overview

Maintenance is what gets full service life out of NB linear motion parts. Grease keeps the rolling elements off the raceways, and regular inspection catches wear before it turns into downtime. The intervals, lubricants, and inspection steps below apply across the NB linear bearing lines.

Lubrication Schedules

How often you re-lubricate depends on the operating conditions. As a baseline:

• Standard conditions: Re-lubricate every 100 km of travel or 6 months
• High-speed applications (>1 m/s): Every 50 km or 3 months
• Dusty/contaminated environments: Every 25 km or monthly
• Cleanroom applications: Use specified low-outgassing grease, 200 km intervals
• Vertical applications: More frequent due to gravity drainage

Recommended Lubricants

For most jobs NB recommends a lithium-based grease (NLGI Grade 2). It needs decent rust prevention and has to be compatible with the seal material. High-speed work runs better on a lower-viscosity oil. Don't mix grease types: incompatible greases can stop lubricating altogether.

Inspection and Replacement Criteria

At each scheduled service, check the bearings for odd noise, added friction, visible corrosion, or excess play. Measure running parallelism now and then to track wear. Replace a bearing when the noise climbs, when positioning accuracy drops below what the application needs, or when you see surface damage like pitting or flaking on the raceways.

Typical Applications

• Preventive maintenance programs
• Machine tool maintenance
• Automated production equipment
• Cleanroom equipment service

Related Products

All NB linear motion products