Inch Standard

Design of Inch-Sized Miniature Bearings

Types:

• Radial,
• Angular contact,
• Full complement,

Radial miniature inch-sized bearings can handle very high radial loads and a small amount of axial load. Angular contact inch-sized miniature bearings can handle very high radial and axial loads. Inch-sized full complement miniature ball bearings are characterized by lower maximum speeds but can handle the highest loads.

Materials:

• Chrome steel,
• Stainless steel,
• Ceramic,
• Plastic,
• Composite materials.

Chrome steel is the most commonly used bearing material due to its high load capacity and low noise characteristics. In applications requiring rust resistance, bearings are usually made from 440c stainless steel, which can withstand high loads and high speeds while also providing rust resistance. For high-speed applications, silicon nitride ceramic miniature bearings are one of the best choices.

ABEC Grades

ABEC-1 to ABEC-9. Factors to consider when choosing an ABEC grade include radial and axial clearances, inner and outer diameter fits, and noise levels. ABEC 3 grade inch-sized miniature bearings are the primary choice for standard applications. Typically, ABEC 5 and higher-grade bearings are more precise and more expensive, generally recommended for precision instruments. Precision miniature bearings' low noise, minimal runout, and long lifespan add to their value.

Seal Types:

• Open,
• Sealed (rubber seal),
• Shielded (metal shield).

Open inch-sized miniature bearings usually use oil lubrication, have low starting torque, and rotate freely. Standard inch-sized bearing seals are made of acrylic/nitrile rubber bonded to metal washers.

Some sizes are equipped with high-temperature PTFE seals (up to 250°C) or Viton seals (up to 230°C). The inner lip of the seal contacts the inner ring of the bearing, effectively sealing out dust and moisture while preventing lubricant leakage. Contact seals generate much higher friction torque levels than shields but reduce the maximum speed of inch-sized miniature bearings. Below -40°C, nitrile and Viton harden and lose their sealing effectiveness, so PTFE seals or metal shields should be considered for extremely low temperatures.

Metal shields are designed to prevent larger particles from entering inch-sized bearings while keeping grease inside. Shields can be pressed into the outer ring of the bearing (non-removable) or secured with a spring snap ring (removable). Since the shields do not contact the inner ring, they do not increase starting or running torque. Shields on stainless steel inch-sized bearings are usually made from AISI 304 stainless steel.

Cages:

• Crowned,
• Ribbon,

Crowned cages: Stamped from stainless steel and guided by the inner ring, they perform excellently in low-torque, low-speed applications. Ribbon cages: Consist of two mating steel components, a cap side, and a finger side. They are usually guided by rolling elements and are designed to reduce friction torque. Riveted cages: RJ-type cages are suitable for larger inch-sized bearings with high load capacity. The two components are riveted together, providing strength sufficient to withstand higher levels of vibration and acceleration. The cages are guided by balls, which help reduce friction torque.

Lubrication

AUBEARING understands the importance of finding the right lubricant for your inch-sized bearing applications. With over 16 years of experience and knowledge, we are confident in matching our customers with the best lubrication solutions. Additionally, we can use customer-specified oils or grease lubricants.

Noise

We provide noise and friction torque specifications through performance testing. The standard instrument for testing the noise of inch-sized bearings is the Anderonmeter, manufactured by Sugawara Laboratories in Japan. An accelerometer contacts the outer ring of the inch-sized bearing to measure noise as the inner ring rotates at 1800 RPM.

Operating Temperature

Standard chrome steel inch-sized bearings can be used at constant temperatures up to 120°C or intermittent temperatures up to 150°C. Beyond these temperatures, the load capacity of chrome steel will decrease. Through special heat treatment processes and the addition of high-temperature grease, we can also customize high-temperature-resistant inch-sized bearings.

Clearance

Internal clearance is the play between the outer ring, inner ring, and rolling elements. Generally, the up-and-down movement of the outer ring relative to the fixed inner ring is called radial internal clearance, and the left-to-right movement is called axial internal clearance. The internal clearance of the bearing in operation is an important factor that affects noise, vibration, heat, and fatigue life, among other factors. AUBEARING's inch-sized miniature bearings offer clearance options: C2, CN, C3, C4, and C5.

AUBEARING has specialized in manufacturing miniature bearings for 16 years, stocking thousands of types of miniature bearings that are rare in the market. AUBEARING is not only a bearing manufacturer but also an expert in providing bearing solutions. We have a strong team of technical engineers and a large service team with extensive end-user service experience and mature industry solutions. We can provide customized services based on your actual working conditions.