Product Introduction

The 61800 Series Deep Groove Ball Bearings belong to the dimension series designated "18" (Width Series 1 + Diameter Series 8) and carry model numbers starting with "618" (e.g., 61804, 61805, 61806). The 618 series shares identical dimensions with the 6800 series; in actual production and application, their inner diameters, outer diameters, and widths are exactly the same, making them interchangeable.

The 61800 series single row Deep Groove Ball Bearings are positioned as a thin-walled, ultra-light series. They feature an outer diameter only slightly larger than the inner diameter and a very narrow width, making them suitable for applications with extremely limited radial space, very light loads, and high rotational speeds.

Single row deep groove Ball Bearings represent the most common type of rolling bearing and have a wide range of applications. They primarily consist of an inner ring, an outer ring, steel balls (rolling elements), and a cage. In addition to open types, these bearings are available with steel dust shields (ZZ type), rubber seals (2RS type), or a snap ring groove on the outer ring (NR type). Pressed steel cages are generally used.

Structure and Characteristics

The structure of the 61800 series is consistent with other single-row deep groove ball bearings, comprising an inner ring, outer ring, steel balls, and a cage, with options for ZZ dust shields or 2RS seals. The thin-walled cross-section design offers the following characteristics:

Thin-walled and lightweight: Small outer diameter, narrow width, and low weight; occupies minimal radial space.

Very high speed: Extremely small steel balls result in minimal centrifugal force and heat generation from friction, placing their limiting speed at the top tier of all deep groove ball bearings.

Minimal friction: Small contact area results in very low starting frictional torque and highly flexible operation.

Very low load capacity: Due to cross-section limitations, the steel balls are tiny and few in number; radial and axial load capacities are very low, making them suitable only for extremely light loads.

Lower rigidity: Thinner rings are prone to deformation, requiring high roundness and precision for the mounting housing bore. Dual Naming System: The same size is designated under both the 61800 series and the 6800 series; please pay attention to the manufacturer's specific naming conventions when purchasing.

Dimensional Specifications

Note: The 61800 and 6800 series share identical dimensions and are interchangeable.

Explanation of Common Suffixes

Open: No seals; suitable for oil lubrication or ultra-high-speed applications.

ZZ / 2Z: Metal shields on both sides; the most common sealing configuration for thin-section series.

2RS: Rubber seals on both sides; protects against dust and water, prevents grease leakage, and is maintenance-free.

C2: Internal clearance smaller than standard; for high-precision, low-vibration applications.

C3: Internal clearance larger than standard; for applications involving temperature rise.

/P5 / P4: High precision grades; the 61800 series is frequently used in precision equipment, offering a wide range of high-precision options.

Key Differences

The 61800 series (equivalent to the 6800 series) represents the "thinnest" end of the deep-groove ball bearing family:

61800/6800 Series (Thin-section): Thinnest and lightest, smallest outer diameter, lowest load capacity, highest speed capability—ideal for precision, light-load applications with extremely limited space.

61900/6900 Series (Thin): Slightly thicker than the 61800 series, with a slightly larger outer diameter and higher load capacity; offers good versatility within the thin-section category.

16000 Series (Extra-light/Narrow): Outer diameter matches the 6000 series, but the width is narrower; positioned between thin-section and standard series.

6000 Series (Extra-light): Enters the standard series category; outer diameter and width are significantly larger than thin-section series; offers moderate load capacity.

6200/6300/6400 Series: Progressively thicker and more robust, with increasing load capacity and decreasing speed capability. 

Application Scenarios

The 61800 series thin-section bearings are primarily used in applications characterized by extremely limited space, light loads, and high speeds:

Precision instruments and meters: Measuring instruments, analytical instruments, optical instruments, and medical equipment—requiring minimal space, very light loads, high precision, and low noise.

Office equipment: Precision rollers and gears for printers, copiers, scanners, and fax machines—requiring compact space and light loads.

Home appliances and smart home devices: Small fan motors, robot vacuums, smart locks, and projectors—requiring compact space and suitability for mass production.

Automotive electronics: Small automotive motors, sensors, and actuators—requiring installation within limited space.

Robotics and automation: Small robot joints, encoders, and harmonic reducers—requiring compact space, light loads, and high precision.

Models and hobbies: High-end model aircraft, model cars, drones, and remote-controlled equipment—where weight and size are critical factors.

Textile machinery: High-speed spindles and yarn-guiding mechanisms—requiring high-speed, light-load capabilities.

Selection Recommendations

1. Verify naming conventions: The 61800 series shares identical dimensions with the 6800 series; confirm the manufacturer's naming convention during procurement to avoid mistaking them for different products due to variations in model designation.

2. Confirm the necessity of thin-section bearings: The 61800 series has very low load capacity, poor rigidity, and a limited selection range; consider this series only when radial space is extremely restricted and the 61900 or 6000 series cannot be used.

3. Rigorously verify load capacity: The 61800 series has a very low load capacity; carefully calculate service life based on actual loads, as even slight overloading can lead to premature failure.

4. Check housing bore precision: The rings of the 61800 series are thin, placing high demands on the roundness, cylindricity, and surface roughness of the housing bore; insufficient bore precision can cause bearing deformation.

5. Exercise extreme caution during installation: Thin-section rings deform easily; apply pressure evenly using specialized tools, strictly avoid striking or tilting the bearing, and consider using a thermal fitting method. 6. Prioritize high precision: The 61800 series is frequently used in precision equipment; selecting a precision class of P5 or higher is recommended.

7. Consider the 61900 series as an alternative: If space permits a slightly larger outer diameter, the 61900 series (also known as the 6900 series) offers superior load-bearing capacity and rigidity compared to the 61800 series, making it a more robust choice.