THK LMF25UU Linear Bushing
The THK LMF25UU is a high-precision linear ball bushing featuring an integrated round flange, engineered for smooth, low-friction linear motion. Its one-piece flange design enables direct, rigid mounting to equipment housings, simplifying installation and ensuring stable guidance. Equipped with double lip seals (UU type) on both ends, it provides superior protection against dust, debris, and lubricant loss, making it ideal for automated machinery, precision instrumentation, 3D printing systems.
The THK LMF25UU is a high-precision linear ball bushing featuring an integrated round flange, engineered for smooth, low-friction linear motion. Its one-piece flange design enables direct, rigid mounting to equipment housings, simplifying installation and ensuring stable guidance. Equipped with double lip seals (UU type) on both ends, it provides superior protection against dust, debris, and lubricant loss, making it ideal for automated machinery, precision instrumentation, 3D printing systems, and general linear motion applications requiring reliable performance and ease of maintenance.
Official Specifications
| Parameter | Value | Unit |
|---|---|---|
| Inscribed Bore Diameter (dₐ) | 25 | mm |
| Bore Diameter Tolerance | 0 / -0.010 | mm |
| Outer Diameter (D) | 40 | mm |
| Outer Diameter Tolerance | 0 / -0.016 | mm |
| Overall Length (L) | 59 | mm |
| Length Tolerance | ±0.3 | mm |
| Flange Diameter (D₁) | 62 | mm |
| Flange Diameter Tolerance | 0 / -0.2 | mm |
| Flange Thickness (H) | 10 | mm |
| Number of Ball Rows | 6 | — |
| Basic Dynamic Load Rating (C) | 980 | N |
| Basic Static Load Rating (C₀) | 1570 | N |
| Mass | 305 | g |
| PCD (Mounting Hole Circle) | 51 | mm |
| Mounting Hole (d₁×d₂×h) | 5.5×9.2×5.4 | mm |
| Radial Clearance | Standard (-9 μm) | μm |
| Maximum Eccentricity | 15 | μm |
| Seal Type | Double Lip Seals (UU, both ends) | — |
| Seal Resistance Force | 0.588 | N |
| Operating Temperature Range | -15°C to +80°C (5°F to 176°F) | °C |
| Standard Lubrication | Factory-pre-lubricated with grease | — |
| Lubrication Methods | Grease, Oil | — |
| Surface Treatment | AP-CF, AP-C, AP-HC, etc. | — |
| Material (Outer Sleeve/Balls) | High-Carbon Chromium Bearing Steel (SUJ2) | — |
| Retainer Material | Synthetic Resin | — |
| Type | Closed Type | — |
Key Features (Official Description)
- Integrated Round Flange: One-piece construction for rigid, flush mounting directly to machine housings, reducing assembly complexity and ensuring alignment accuracy.
- 6-Row Ball Architecture: Delivers high radial load capacity, exceptional rigidity, and smooth, low-friction linear movement.
- Dual UU Seals: Provides effective dust protection and prevents lubricant leakage, extending service life in contaminated environmentsTHK.
- High Precision Manufacturing: Strict dimensional tolerances on bore, outer diameter, and eccentricity guarantee stable, low-noise operation.
- Temperature-Constrained Design: Equipped with a synthetic resin retainer; continuous operation must not exceed 80°C to ensure material integrity.
- Maintenance-Friendly: Pre-lubricated at the factory; compatible with standard relubrication procedures for extended performance.
Official Application Notes
- Shaft Requirements: Recommended shaft hardness: 60–64 HRC; surface roughness: Ra ≤ 0.8 μm.
- Load Capacity: Designed primarily for radial loads; not suitable for pure moment or axial loads.
- Temperature Limit: Continuous operating temperature shall not exceed 80°C to prevent degradation of the resin retainer and seals.
- Alignment: Ensure proper shaft alignment to avoid binding and premature wear.
Model Variants: Available in stainless steel versions for corrosive environments and long types (LMF25LUU) for increased moment load resistance.
