EF series ball screw end support

I. Core Positioning and Nomenclature

Positioning: A floating end support unit for ball screws that uses an eccentric locking collar to connect to the screw shaft.

Nomenclature Interpretation:

• E: Stands for "Eccentric," referring to its core locking principle (same as EK).
• F: Stands for "Free" or "Float." This is its functional core (same as BF).

Core Value: It combines the installation convenience of the eccentric locking collar with the thermal expansion relief function of the floating end, providing a perfect standardized solution for the floating end of plain shaft ball screws without shoulders.

II. Core Structure and Working Principle

The EF unit is a fusion of structure (E-type locking) and function (F-type floating):

Eccentric Locking Collar Mechanism:
Uses identical components to the EK unit. A slotted sleeve with an eccentric lug and a locking ring securely connects the support unit to the plain screw shaft using radial clamping force.

• Key Difference: In the EF, this locking mechanism is responsible only for radial locking and torque transmission (if needed), not for restricting axial movement.

Floating Bearing Mechanism:
Internally, it typically employs a deep groove ball bearing (same as BF). The bearing outer ring is axially located at one end within the housing, with clearance left at the other end.
The bearing inner ring has an interference or tight fit with the eccentric sleeve, which in turn grips the screw shaft via friction. Therefore, the entire bearing-eccentric sleeve assembly can slide axially within the housing.

Working Principle Process:

• Radial: Locking ring is tightened → Eccentric sleeve grips the screw shaft → Screw shaft's radial position is precisely located.
• Axial: Screw expands due to heat → Force is transmitted via friction to the eccentric sleeve → Eccentric sleeve causes the entire bearing to slide axially within the housing → Thermal stress is relieved.

III. Core Features and Advantages

Perfect Match for EK Fixed End:
This is the most typical and logical application scenario for EF. When the fixed end uses EK (due to employing a plain shaft screw), the floating end should naturally be EF to maintain consistency in the locking method and installation convenience. They are inherent partners.

Suitable for Floating End of Plain Shafts Without Shoulders:
Solves the problem of how to reliably connect and allow axial float for plain shaft screws at the floating end. No need to machine any steps or threads on the plain shaft for axial limitation.

Combines Installation Convenience and Floating Function:

• Installation Convenience: Inherits all advantages of E-type locking—after the screw is inserted, tightening one locking ring completes the connection; position is adjustable, and disassembly is easy.
• Ensures Floating: Its internal structure is carefully designed to strictly guarantee axial free float while providing radial locking.

Saves Axial Space:
Like EK, the EF has a compact structure. It does not rely on shaft shoulders and retaining rings for axial limitation (in some designs) like traditional BF units, benefiting space-constrained layouts.

IV. Golden Combination for System Pairing

For a typical cost-effective, easy-to-install system using standard plain shaft ball screws, the optimal support combination is:

• Drive Side / Fixed End: EK
• Non-Drive Side / Floating End: EF

This combination achieves:

• Zero Screw Machining: No need for turning shoulders, milling keyways, or tapping threads.
• Extremely Simplified Installation: Both ends use a simple "insert shaft - tighten" operation.
• Complete Performance: Fully possesses the rigid positioning of the fixed end and the thermal expansion compensation function of the floating end.

V. Comparison with BF Floating End

VI. Typical Application Fields

The application scenarios for EF support units are closely linked to its partner EK, particularly suitable for:

• All automation equipment using standard plain shaft ball screws: e.g., linear modules, precision slides.
• Situations with high requirements for installation efficiency and maintenance convenience: e.g., mass-produced equipment, production lines requiring on-site quick debugging or screw replacement.
• Compact space designs preferring a simple screw shaft end structure.
• Feed axes using plain shaft ball screws in small to medium CNC machines, laser processing equipment, and robots.

VII. Selection and Usage Guidelines

Systematic Selection: EF should not typically be selected alone but considered as a system together with the EK fixed end.

Confirm Screw Type: Must confirm the use of a plain shaft ball screw without shoulders.

Correct Installation:

• Ensure the EF unit is installed on the non-drive end of the screw (the end away from the motor).
• Clean the contact surfaces of the screw shaft and eccentric sleeve.
• Tighten the locking ring to the specified torque. After tightening, manually confirm the screw shaft can slide smoothly within the EF unit (usually with slight resistance but no sticking)—this is key to verifying its floating function.

Avoid Additional Axial Constraints: Like BF, at the EF end, the screw shaft must not be connected to any component that would restrict its axial float (e.g., a rigidly connected encoder).

The EF support unit is an ingenious crystallization of eccentric locking technology (E) and floating end functionality (F). It fills the standardization gap for "floating end support for plain shaft ball screws." Together with the EK fixed end, it forms a complete, elegant, and user-friendly ball screw support solution. Choosing EF (paired with EK) means opting for an engineering path that maximizes installation convenience, minimizes screw machining costs, and sacrifices no core performance. It represents the thorough implementation of the modern mechanical design philosophy of "easy to manufacture, easy to assemble, easy to maintain."