Customized Ruby Bearings Al₂O₃ Jewel Bearings for Precision Instruments and Watch Movements

Ruby Bearing Product Overview

Customized ruby bearings are made from synthetic corundum (Al₂O₃) doped with chromium to achieve their characteristic red color. Through precision machining, they can be produced in spherical, conical, or straight-hole geometries. Ruby bearings are essential components in precision mechanical systems, providing extremely low friction, enhanced dimensional stability, high wear resistance, and long service life. They perform reliably in high-temperature, corrosive, and vibration-intensive environments, making them ideal for precision instruments and high-sensitivity devices.

Ruby bearings are widely used in watch movements, metering instruments, aerospace navigation systems, and other applications requiring ultra-stable mechanical support and micro-scale friction reduction.

Ruby Bearing Key Features

1. Material Properties

• High Hardness: Mohs hardness of 9 and Knoop hardness around 1,800, far superior to metal bearings in wear resistance.

• Low Friction Coefficient: 0.10–0.15 (ruby vs. steel), significantly reducing frictional loss and improving responsiveness.

• Corrosion Resistance: The stable alumina crystal withstands acids, alkalis, oxidation, and moisture.

2. Performance Advantages

• High-Temperature Resistance: Operates stably above 800°C with low thermal expansion and excellent thermal shock stability.

• Lubrication-Free Design: Extremely smooth crystal surface reduces the need for long-term lubrication.

• Fatigue Resistance: Dense crystalline lattice ensures very low wear and deformation under continuous micro-loading.

3. Application Adaptability

• Low-Load, High-Sensitivity Systems: Ideal for watch pivots, escapement wheels, micro-meter mechanisms, and galvanometer pointers.

• Customizable Geometry: Available in spherical, conical, ring-type, and straight-hole forms, adjustable to specific design requirements.

• Consistent Performance: Offers long-term reliability even in demanding environments such as high humidity, high temperature, or corrosive media.

Ruby Bearing Applications

1. Watch Movements

Used in balance wheel pivots, escape wheels, and gear train pivots. Typical mechanical watches use 17–25 ruby jewels to minimize friction, improve accuracy, and extend service life.

2. Precision Instruments

Applied in galvanometers, micrometers, gyroscopes, high-sensitivity sensors, and metrology equipment to ensure smooth motion, low drift, and superior stability.

3. Military and Aerospace

Used in high-precision navigation systems, stabilized platforms, and vibration-intensive instruments requiring long-term accuracy and environmental resistance.

Ruby Bearing Key Parameters

Ruby Bearing FAQ

1. Why is ruby used for bearings?

Ruby offers exceptional hardness, low friction, and high wear resistance, making it ideal for precision and long-term durability in mechanical systems.

2. What are jewel bearings used for?

They are used in watches, precision measuring instruments, gyroscopes, and medical devices to reduce friction, improve accuracy, and ensure smooth, stable movement.

3. Do ruby bearings require lubrication?

Generally no. The polished crystal surface provides naturally low friction, allowing lubrication-free operation in many applications.

4. Can ruby bearings operate in harsh environments?

Yes. Ruby is chemically inert and highly resistant to corrosion, extreme temperatures, and humidity, making it suitable for aerospace, laboratory, and industrial environments.

5. Are ruby bearings suitable for high-speed rotation?

Yes. Their low friction and excellent dimensional stability allow them to perform well in high-speed, micro-rotational systems such as watch escapements and micro-motors.

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