Sapphire Jewel Bearing Applications

Custom fabricated sapphire windows & lenses which are chemically inert and operate over a wide spectrum for use in blood gas monitors, centrifuges, and other instruments are available from AOG Sapphire Optics Co.,Ltd.

Sapphire Jewel Bearing

Flow Meters, Gauges, Meters, Indicators, Aircraft Instruments, Gyros, Watches, Clocks.

Sapphire Jewel bearings are normally mounted in some type of housing. This housing may be a screw, bushing or plate fabricated from half hard brass, C.R.S., stainless, aluminum or other metals. Mounting is generally accomplished by spin setting or friction set. By this method, the jewel is forced into a hole drilled to create interference fit with the OD of the jewel.

Spin setting is the more generally used and more satisfactory mounting method because minimum pressure is applied on the jewel, and there is less danger of breakage or damage. The jewel is placed in position in the hole and setting material is spun over the edge of the jewel to hold it in place.

Spring-loaded mounts offer a factor of safety in jewel bearing assembly and jewel bearing application. With rigid mountings, excessive tightening of the jewel bearing can cause the pivot to bottom with the possibility of damage to the jewel bearing or pivot. With spring set jewels, the jewel bearing adjustment is not critical.

Sapphire Ring Jewel Bearings serve as radical or sleeve jewel bearings used with a straight cylindrical shaft. They offer a great flexibility in jewel bearing design because of the many possible combinations with endstones. Rugged straight hole rings restrict lateral movement to a minimum but require accurate alignment when the clearance between pivot and the jewel bearing is closely held. An olive hole (radiused ID) jewel offers lower friction bearings with the pivot and permits adjustment in the jewel bearing assembly. A bombé face provides minimum contact with a shouldered pivot for light, intermittent end thrust. Where thrust load is continuous, an endstone is usually combined with the ring jewel.

Typical Sapphire Ring Jewel Bearing Applications: General Instrumentation, Gauges, Meters, Indicators, Watches, Clocks, Potentiometers, Gyros, Aircraft Instruments.

Sapphire Vee Jewel Bearings are well suited to sensitive instruments where the moving element is light. They offer minimum friction when used with conical, small radiused pivots and permit slight lateral movement. The jewel radius should be 3 times larger than the pivot radius for low friction torque, sensitivity, and resistance to deformation. The contact area of the pivot should be highly polished and a micro-inch finish of 2 or better on the pivot radius is recommended.

Typical Sapphire Jewel Bearing Applications: Ohmmeters, Voltmeters, Gauges, and other Indicating Meters; Timers and Relays.

Sapphire Cup Jewel Bearings are generally used with a semi-spherical pivot or in a jewel bearing design that fits a ball bearing between two cup jewels. They are widely used for vertical shaft applications.

Typical Sapphire Cup Jewel Bearing Applications: Compasses, Heat Monitors.

Sapphire Orifice Jewels are a development of the vee jewel and are sometimes called drilled vees. Sapphire is an excellent orifice material because of its resistance to wear, heat and corrosion, as well as its low friction. The hole diameter for control purposes is usually specified to be held within 0.0002”. Sapphire orifices can be used for UHP water jet applications (up to 40,000-50,000 PSI), oil atomizing and the handling of air, hot gases and practically all liquids and acids.

Typical Sapphire Orifice Jewel Applications: Control Units (gas, liquid), Flow-meters, Ultra-High Pressure Water Jet, Ink Jet Printing.