Rodamientos de rodillos cruzados are high-precision, rigid bearings designed for applications requiring excellent rotational accuracy and stiffness. They achieve this by incorporating cylindrical rollers arranged in a ‘V’ forma, with alternate rollers oriented at 90 degrees to each other. This configuration allows a single bearing to handle radial, axial, y cargas de momento simultáneamente.
Key Technical Specifications of Crossed Roller Bearings
1. Dimensiones (Bore, Diámetro externo, Ancho):
Analysis: These are fundamental for fitting the bearing into your design. Precise machining of the housing and shaft is crucial for optimal performance. Variations in these dimensions beyond tolerance can lead to misalignment, reduced life, and increased friction.
2. Accuracy Class (P0, P6, P5, P4, P2):
Analysis: This specifies the geometric precision of the bearing components (p.ej., runout, parallelism, perpendicularity).
P0 (Normal Class): Suitable for general industrial machinery where high precision isn’t paramount.
P6, P5, P4, P2 (Higher Precision): Progressively higher accuracy, used in applications like machine tool turntables, robotic joints, and measurement equipment where precise positioning and minimal runout are critical. Higher accuracy generally means tighter tolerances, better surface finish, and more stringent manufacturing processes, leading to higher cost.
3. Rotational Accuracy:
Analysis: This refers to the precision of the bearing’s rotation. Key parameters include:
Desviación radial: Variation in the radial position of the inner or outer ring during rotation.
Desviación axial: Variation in the axial position of the inner or outer ring.
Perpendicularity of Mounting Surface to Axis: How precisely the mounting face is perpendicular to the bearing’s rotational axis.
Importance: Critical for applications requiring precise angular positioning, such as rotary tables in CNC machines or robotic manipulators.
4. Load Ratings (Basic Dynamic Load Rating C, Basic Static Load Rating C0):
Analysis: These values, determined by ISO standards, indicate the bearing’s capacity to handle loads.
do (Dynamic): The constant radial load that a group of apparently identical bearings can theoretically endure for a basic rating life of one million revolutions. Used for applications with continuous rotation under load.
C0 (Static): The static radial load which corresponds to a total permanent deformation of rolling element and raceway at the most heavily stressed contact of approximately 0.0001 of the rolling element diameter. Used for applications with static loads, slow oscillation, or infrequent rotation.
Selección: The required load rating depends on the applied loads, desired service life, y condiciones de funcionamiento. Safety factors are often applied, especially for shock loads.
5. Permissible Rotational Speed (Grease Lubrication, Oil Lubrication):
Analysis: This indicates the maximum speed the bearing can operate at without excessive heat generation or premature wear.
Factors affecting speed: Lubrication type (oil allows higher speeds), internal clearance, cage design, y de refrigeración.
Consequences of exceeding: Overheating, lubrication breakdown, accelerated wear, and potential bearing failure.
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