How are the vibration and noise levels of 63 series bearings divided

In high-precision machinery, the performance of rolling bearings—particularly the widely utilized 63 Series Deep Groove Ball Bearings—is critical. Among the key performance indicators, the Vibration Grade and Noise Grade stand out as essential metrics for quality assessment and application suitability. These classifications are established based on stringent international and industry standards, such as ISO and GB/T, quantifying the bearing’s vibrational acceleration or velocity and sound pressure level under specified operating conditions.

In modern high-speed motors, precision equipment, and noise-sensitive devices, the demand for quiet and stable bearing operation is escalating. A thorough understanding of the 63 Series Vibration Grade and Noise Grade methodology is vital for equipment design, selection, fault diagnosis, and ensuring the stability of the final product.

I. Professional Segmentation of 63 Series Bearing Vibration Grade

Bearing vibration originates from factors including the geometric precision of the raceways, rolling elements, and cage, as well as surface quality and mounting conditions. The Vibration Grade is typically measured using Vibration Velocity or Vibration Acceleration, segmented across specific frequency bands under controlled testing environments.

1. Vibration Measurement Standards and Methodology

Vibration testing for 63 Series bearings must be performed on standardized Vibration Measuring Instruments. The primary method involves measuring the root mean square (RMS) value of the radial vibration velocity across three designated frequency bands while the bearing rotates at low to medium speeds:

• Low Frequency Band (L): Typically $50\text{ Hz}\sim 300\text{ Hz}$. This band predominantly reflects the bearing’s Geometric Non-Roundness, Raceway Waviness, and Raceway Pits. It is also linked to the operational stability of the cage.
• Medium Frequency Band (M): Typically $300\text{ Hz}\sim 1800\text{ Hz}$. This is the core band for quality assessment, primarily reflecting the Surface Quality and Micro-Waviness of the rolling elements and raceways.
• High Frequency Band (H): Typically $1800\text{ Hz}\sim 10000\text{ Hz}$. This band is indicative of the bearing’s Cleanliness, minute defects, and high-frequency noise sources.

2. Vibration Grade Designations and Implications

Based on the measured vibration values, the 63 Series Vibration Grade is categorized into the following standard levels, conforming to national (e.g., GB/T 307.3-2017) and international standards:

Expert Interpretation: In bearing model designations, suffixes like V1, V2, or V3 typically denote the Vibration Grade. A 63 Series bearing with a V2 Grade exhibits significantly lower vibration values in the M frequency band compared to a V1 Grade bearing. This ensures superior smoothness at medium operating speeds, making it the preferred choice for mid-to-high-end motor applications.

II. Professional Segmentation of 63 Series Bearing Noise Grade

The Noise Grade is a crucial parameter for evaluating the bearing's Quietness during operation. Noise primarily stems from bearing vibration, collision between rolling elements and the cage, and sound waves generated by lubricant flow. Noise measurement is fundamentally based on the Sound Pressure Level.

1. Noise Measurement Standards and Instruments

Noise level measurement requires a strictly controlled environment, necessitating testing in an Anechoic Chamber or on a Low-Noise Test Rig. Specialized Sound Level Meters are used to record the A-weighted sound pressure level of the bearing at a specific rotational speed. Results are commonly expressed using the median or maximum value of the sound pressure level.

2. Noise Grade Designations and Implications

The 63 Series Noise Grade classification, denoted by the Z series of suffixes, complements the Vibration Grade but focuses specifically on acoustics:

Expert Interpretation: 63 Series bearings with Z2 Grade typically feature higher precision rolling elements, optimized cage designs, and strictly screened low-noise specialty grease. In model suffixes, for instance, “6304-2Z/Z2” indicates a bearing with double shields (2Z) and a Z2 Grade low-noise performance. Achieving Z2 Grade is essential for maintaining acoustic quality in consumer electronics.

III. Interconnection and Selection Strategy

While the Vibration Grade and Noise Grade measure distinct physical phenomena, they are intrinsically linked: Low vibration is the foundation for achieving low noise.

• Vibration as the Noise Source: Bearing vibration transmits through the shaft, housing, and mechanical structure, eventually radiating as audible noise. Consequently, V3 Grade bearings often meet the requirements for Z3 Grade noise levels.
• Lubricant Impact: The type, fill quantity, and cleanliness of the Lubricant significantly influence high-frequency vibration and noise (H band, Z2/Z3 grades). Using high-quality, low-noise specialty grease is crucial for enhancing the quietness of 63 Series bearings.

When selecting a 63 Series bearing for a specific application, the required grade should align with the end product’s Functional Requirements and Market Positioning:

• For vibration-sensitive equipment (e.g., high-speed grinding machine spindles), the focus must be on the Vibration Grade (e.g., V2 or V3).
• For equipment demanding superior quietness (e.g., air conditioning indoor units, high-end vacuum cleaners), the focus must be on the Noise Grade (e.g., Z2 or Z3).