Product Introduction

The 6800 series Deep Groove Ball Bearings belong to the thin-section category of single-row Deep Groove Ball Bearings, often referred to as the "extra-light series." Model numbers begin with "68" (e.g., 6804, 6805, 6806). The 6800 series serves as the "mainstay" of thin-section bearings: it is more practical than the 6700 ultra-thin series and lighter/thinner than the 6900 series. Widely used in applications requiring space efficiency, light loads, and high speeds, it is the most commonly utilized type within the thin-section range.

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 designs, these bearings are available with steel dust shields (ZZ type), rubber seals (2RS type), or snap rings on the outer ring (NR type). Pressed steel cages are typically used.

These bearings feature low frictional torque, making them ideal for environments requiring high rotational speeds, low noise, and low vibration. They primarily support radial loads but can also handle limited bidirectional axial loads. When radial internal clearance is increased, the bearing exhibits characteristics similar to an angular contact ball bearing, allowing it to withstand alternating axial loads in both directions.

Structure and Characteristics

The 6800 series features a compact cross-section—the outer diameter is only slightly larger than the inner diameter, and the bearing width is narrow. This thin-section design offers the following characteristics:

Thin-section and Lightweight: Small outer diameter, narrow width, and low weight; occupies minimal radial space, making it suitable for compact equipment.

High Rotational Speed: Smaller steel balls result in lower centrifugal force and reduced frictional heat generation, allowing for high limiting speeds—second only to the 6700 and 6000 series.

Low Friction: Smaller contact area results in low starting frictional torque and smooth operation.

Lower Load Capacity: Due to cross-section constraints, the steel balls are smaller and fewer in number, resulting in lower radial and axial load capacities; suitable only for light-load applications. Moderate Rigidity: The rings are relatively thin, resulting in lower rigidity compared to the 6000 or 6200 series; this places specific demands on the precision of the mounting bore.

Wide Selection: Specifications range from small to large sizes, offering a broader variety of sealing options and precision grades than the 6700 series.

Good Cost-Performance Ratio: As a high-volume, mature product line within the thin-wall category, it is more affordably priced than the 6700 series.

Dimensional Parameter Table

Common Suffixes

Open: Standard 6800 series products are available in open configurations, suitable for oil lubrication or self-lubrication.

ZZ / 2Z: Double-sided metal shields; the most common sealing type for thin-wall series; protects against dust but not water.

2RS: Double-sided rubber seals; protect against dust, water, and grease leakage; maintenance-free; suitable for humid and dusty environments.

C2: Internal clearance smaller than standard; suitable for high-precision, low-vibration applications; relatively common in thin-wall series.

C3: Internal clearance larger than standard; used in operating conditions involving temperature rise.

/P5 / P4: The 6800 series is frequently used in precision equipment, offering a wide range of high-precision grade options.

Cage: Pressed steel cages are most common, though copper alloy and nylon cages are also available.

Application Scenarios

6800 series thin-wall bearings are widely used in applications requiring space efficiency, light loads, and high speeds:

Office Equipment: Roller and gear supports for printers, copiers, scanners, and fax machines—characterized by limited space, light loads, and low-noise requirements.

Home Appliances & Smart Home: Motors for AC fans, washing machines, vacuum cleaners, robot vacuums, and smart locks—characterized by compact space, light loads, and mass production.

Automotive Parts: Wiper motors, seat adjustment motors, sunroof motors, blower motors, and automotive electronics—characterized by limited installation space.

Precision Instruments & Medical Equipment: Measuring instruments, analytical instruments, dental handpieces, and small pumps—characterized by miniaturization, low noise, and high precision.

Robotics & Automation: Small robot joints, encoders, harmonic reducers, and servo motors—characterized by compact space, light loads, and high precision. Power tools: Small electric drills, angle grinders, sanders — limited space, high rotational speeds.

Textile machinery: High-speed spindles, yarn-guiding mechanisms, knitting machines — high speed, light load.

Models and hobbies: Model aircraft, model cars, drones, 3D printers — sensitive to weight and size constraints.

Bicycles and sports equipment: Bicycle hubs, pulleys, fitness equipment — light load, requirement for lightweight components.

Key Differences

The 6800 series occupies a "medium-thin" position within the thin-section bearing category; its distinctions from other series can be understood as follows:

6700 series (Ultra-thin): Thinner and lighter than the 6800 series, with a smaller outer diameter and lower load capacity; used in extremely space-constrained applications, though options are limited and prices are high.

6800 series (Thin-section): The mainstay of the thin-section category; more practical than the 6700 series and lighter/thinner than the 6900 series; offers a good balance of performance and cost, making it the most commonly used thin-section series.

6900 series (Thin): Slightly thicker than the 6800 series with a marginally larger outer diameter; offers superior load capacity and rigidity, and is the most versatile of the thin-section series.

6000 series (Extra-light): Transitions into the standard series; outer diameter and width are significantly larger than thin-section series; offers moderate load capacity and good versatility.

6200/6300/6400 series: Increasingly robust and heavy-duty; higher load capacities and lower rotational speeds; these belong to a different application range than thin-section bearings.

A direct comparison using a 25mm inner diameter: The 6805 has an outer diameter of 37mm and a width of 7mm, whereas the 6205 has an outer diameter of 52mm and a width of 15mm. The 6805's outer diameter is 15mm smaller than the 6205's, and its width is less than half that of the 6205. While the 6805's load capacity is only about one-third that of the 6205, it supports higher rotational speeds and is lighter in weight. 

Selection Recommendations

Check for space constraints: The 6800 series has a lower load-carrying capacity; consider it only when radial space is limited and the 6000 or 6200 series cannot be used. If space permits, the 6000 or 6200 series offers superior load capacity and cost-effectiveness.

Verify load capacity: Due to the lower load capacity of the 6800 series, calculate the service life based on actual loads to ensure requirements are met. Overloading is a primary cause of premature failure in thin-section bearings.

Check housing bore precision: The 6800 series features thin rings, placing specific demands on the roundness and cylindricity of the housing bore. Insufficient precision can lead to bearing deformation and increased noise.

Ensure proper installation: Apply pressure evenly using specialized tools; avoid striking or tilting the bearing. For significant interference fits, thermal mounting is recommended to prevent ring deformation during press-fitting.

Select the right seal: Choose ZZ for dry environments (high speed), 2RS for humid or dusty conditions (maintenance-free), and open bearings for oil lubrication or ultra-high-speed applications.

Select the precision class: Choose P0 for general operating conditions, P5 for precision equipment or low-noise requirements, and P4 for ultra-precision applications.

Ensure appropriate lubrication: Thin-section bearings have limited internal space; limit grease fill to 1/3–1/2 of the capacity, as excessive grease causes heat generation due to churning.

Consider the 6900 series as an alternative: If a slightly larger outer diameter is permissible, the 6900 series offers better load capacity and rigidity than the 6800 series, making it a more robust choice.