SFU series ball screw

The term "SFU Ball Screw" typically refers to a high-precision ball screw and its integrated support unit that conforms to international standards (such as JIS, DIN). It is not a single product but a standardized, modular transmission component system integrating a high-precision ball screw, precision support bearing housings (fixed side and support side), seals, and a lubrication system.

Its core feature is the significant simplification of the installation, alignment, and maintenance processes for the ball screw assembly, achieving a high-performance, "ready-to-install" solution.

Introduction

I. Core Advantage: Standardization and Modularity

This is the most fundamental feature of the SFU ball screw. Manufacturers provide a series of standard sizes and accuracy grades for screws, nuts, and matching support units. Users only need to select the corresponding model based on load, speed, accuracy, and installation dimensions, eliminating the need to design separate bearing housings or perform complex alignment and adjustments.

Advantage: Significantly reduces design, procurement, and assembly time, lowers overall costs, and improves equipment reliability.

II. High Precision and High Performance

The SFU ball screw typically refers to precision ball screws of grade C3-C7 (or higher).

High Transmission Efficiency: Ball screw transmission efficiency can exceed 90%, far superior to trapezoidal (acme) screws (~20-50%).
High Positioning and Repeat Positioning Accuracy: High lead accuracy and low backlash (which can be eliminated via preload) enable precise motion control at the micron level.
Smooth Motion: Rolling contact of the balls results in low starting torque, responsive movement, and eliminates stick-slip (crawling) even at low speeds.

III. Design Features of the Support Unit

The support unit is a key component of the SFU system and includes:

Fixed Side Support Unit:

Typically incorporates angular contact ball bearings (used in pairs) capable of withstanding both axial and radial loads, offering high rigidity.
Includes a preload adjustment mechanism to optimize bearing rigidity and eliminate clearance.
Integrated labyrinth or contact seals effectively prevent dust ingress and grease leakage.
Features a standard grease nipple for easy periodic maintenance.

Support Side (Simple Side) Support Unit:

Uses deep groove ball bearings or plain bushings, primarily to support radial loads. It allows slight axial float of the screw shaft due to thermal expansion, preventing internal stress from thermal deformation.
Also includes a sealing structure.

IV. High Rigidity and Long Service Life

High System Rigidity: The precision bearing configuration and appropriate preload result in excellent axial rigidity for the entire transmission system, providing strong resistance to load-induced deformation.
Long Service Life: The point contact of the balls allows for mature theoretical life calculations. With correct installation, adequate lubrication, and good dust protection, the service life is exceptionally long. After wear, typically only the nut or screw needs replacement, while the support unit can be reused.

V. EasyInstallationand Maintenance

Ready-to-Install: The mounting surfaces of the support units are precision machined. Installation mainly involves bolting the units to the machine base, pressing the screw shaft shoulder against the inner ring of the fixed side bearing, and tightening the locknut. This greatly reduces dependency on the skill level of assembly personnel.
Easy Alignment: The design of the support unit ensures good alignment between the bearings and the screw axis.
Convenient Maintenance: Standardized lubrication interfaces make greasing maintenance very simple. The effective sealing system extends maintenance intervals.

VI. Extensive Options and Compatibility

Multiple Accuracy Grades: From standard to precision grades, meeting different application needs.
Multiple Preload Grades: Such as no preload, light preload, medium preload, and heavy preload, allowing users to choose based on rigidity and friction requirements.
Multiple Nut Formats: Typically a standard flanged nut for easy installation.
Direct Motor Connection: The screw end can be machined as a plain shaft, with flats, keyways, or as a flexible/rigid coupling interface for direct connection to servo or stepper motors.

VII. Typical Application Fields

Due to its excellent performance, the SFU ball screw system is widely used in applications requiring precision linear motion:

CNC Machine Tools: Feed axes for machining centers, lathes, milling machines, grinders.
Semiconductor Equipment: Wire bonders, inspection equipment, die bonders.
Industrial Robots: Joint drives, linear motion units.
Precision Measuring Equipment: Coordinate Measuring Machines (CMMs), vision measuring systems.
Automation Equipment: Assembly lines, handling devices, laser processing equipment, printing equipment, etc.

In essence, the SFU ball screw system elevates the high-performance ball screw from a "component requiring precision assembly" to an "easy-to-use, standardized functional unit." Through thoughtful integrated design, it provides users with a complete, ready-to-install linear motion solution offering high precision, high rigidity, and long service life. It is an indispensable key foundational component in the design of modern precision machinery and equipment.