- English
- Chinese
- French
- German
- Portuguese
- Spanish
- Russian
- Japanese
- Korean
- Arabic
- Irish
- Greek
- Turkish
- Italian
- Danish
- Romanian
- Indonesian
- Czech
- Afrikaans
- Swedish
- Polish
- Basque
- Catalan
- Esperanto
- Hindi
- Lao
- Albanian
- Amharic
- Armenian
- Azerbaijani
- Belarusian
- Bengali
- Bosnian
- Bulgarian
- Cebuano
- Chichewa
- Corsican
- Croatian
- Dutch
- Estonian
- Filipino
- Finnish
- Frisian
- Galician
- Georgian
- Gujarati
- Haitian
- Hausa
- Hawaiian
- Hebrew
- Hmong
- Hungarian
- Icelandic
- Igbo
- Javanese
- Kannada
- Kazakh
- Khmer
- Kurdish
- Kyrgyz
- Latin
- Latvian
- Lithuanian
- Luxembou..
- Macedonian
- Malagasy
- Malay
- Malayalam
- Maltese
- Maori
- Marathi
- Mongolian
- Burmese
- Nepali
- Norwegian
- Pashto
- Persian
- Punjabi
- Serbian
- Sesotho
- Slovak
- Slovenian
- Somali
- Samoan
- Scots Gaelic
- Shona
- Sindhi
- Sundanese
- Swahili
- Tajik
- Tamil
- Telugu
- Thai
- Ukrainian
- Urdu
- Uzbek
- Vietnamese
- Welsh
- Xhosa
- Yiddish
- Yoruba
- Zulu
- Kinyarwanda
- Tatar
- Oriya
- Turkmen
- Uyghur
Category
K21X25X13
Needle roller bearings utilize cylindrical rollers with a length-to-diameter ratio exceeding 4:1. This “needle-like” geometry enables exceptional radial load capacity within extremely compact cross-sections, providing superior space efficiency compared to ball bearings of equivalent dimensions.
Needle Roller Bearings
| ISO | K21X25X13 | |
| Raceway diameter inner ring | Fw | 21 mm |
| Outside diameter | Ew | 25 mm |
| Width | Bc | 13 mm |
| Basic dynamic load rating | C | 4.85 kN |
| Basic static load rating | C0 | 7.25 kN |
| Limiting speed | 10100 r/min | |
| Mass bearing | 0.009 kg | |
Structural Breakdown
Key components include:
- Outer Ring: Typically with raceway (cageless types omit outer ring)
- Needle Rollers: Precision-ground rollers transmitting load via line contact
- Cage: Brass/steel/polymer material spacing rollers (cageless types exclude cage)
- Inner Ring: Optional component (e.g., NA-type with inner ring, RNA-type without)
Classification System
- By Design: Full complement (high load), caged (high-speed capable)
- By Function: Radial, thrust, combination bearings
- Special Types: Flanged (axial positioning), aligning (misalignment compensation)
Technical Advantages
| Feature | Engineering Benefit |
| Ultra-slim section | Saves 60% radial space |
| High load density | 300% higher capacity vs. balls |
| Shock resistance | Line contact distributes stress |
| Rotation accuracy | ±0.03mm for precision systems |
| Note: Speed limitation varies by cage material |
Industry Applications
- Automotive: Transmissions (e.g., JTEKT NK17/20), connecting rods
- Robotics: Articulated joints (full complement type prevalent)
- Aerospace: APU rotor support bearings
- Medical: CT scanner gantry rotation (MRI-safe versions)
- Construction: Hydraulic pump drives (Timken TOR 47)
Environmental Adaptation
| Condition | Recommended Solution |
| High temperature | Ceramic-coated rollers + special cages |
| Corrosive media | Full stainless steel (SS suffix) |
| Contaminated areas | Double-lip contact seals (2RS) |
| Ultra-high speed | Polymer cages + oil-air lubrication |
Contact Us
Related Products
NJ214
Cylindrical roller bearings are rolling bearings specifically engineered to accommodate high radial loads. Their key rolling elements are cylindrical rollers that make linear contact with the raceways. This design makes them exceptionally effective at handling pure radial forces, serving as critical components in a vast array of industrial applications. Compared…
K20X28X20
Needle roller bearings utilize cylindrical rollers with a length-to-diameter ratio exceeding 4:1. This “needle-like” geometry enables exceptional radial load capacity within extremely compact cross-sections, providing superior space efficiency compared to ball bearings of equivalent dimensions.
UCFL315-48
The UC series bearings refer to standardized, widely-used pillow block ball bearing units with adapter sleeves. At their core is a deep groove ball bearing featuring a spherical outer diameter (SPB) designed to fit into the matching spherical bore of a cast iron housing. Adhering to metric dimensions, this series is…
UCFL305-14
The UC series bearings refer to standardized, widely-used pillow block ball bearing units with adapter sleeves. At their core is a deep groove ball bearing featuring a spherical outer diameter (SPB) designed to fit into the matching spherical bore of a cast iron housing. Adhering to metric dimensions, this series is…
UK218-H2318
The UC series bearings refer to standardized, widely-used pillow block ball bearing units with adapter sleeves. At their core is a deep groove ball bearing featuring a spherical outer diameter (SPB) designed to fit into the matching spherical bore of a cast iron housing. Adhering to metric dimensions, this series is…
626 2RS
A Deep Groove Ball Bearing is one of the most widely used types of rolling bearings. It consists of an inner ring, outer ring, steel balls, and a cage (or sealing components). The deep groove raceways on the inner and outer rings allow it to withstand radial loads and limited…
-
-
-
grashbearings@outlook.com
-
+86-13863568175