Aerospace Bearings
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Aerospace Bearings Bearing Selection Smith Aircraft Bearings presented in this section have been designed to meet the standards of the aerospace industry and conform to military and other appropriate national standards. When selecting these bearings for your application, it is recommended that you review the engineering data provided, along with any appropriate military or national specifications. YAF (MS21438) & YAT (MS21439) YAF and YAT Series Yoke Type bearings have heavy outer ring sections and were designed for application as track rollers where the bearing O.D. is unsupported. These bearings will support heavy rolling or oscillating loads in cam or track roller applications. The YAF-Series (single row) needle bearings have a crowned outer race. The YAT-Series (double row) needle bearings have large blended outside corner radiuses to help distribute stresses. The outer race is hard-chrome plated and all other exposed surfaces are cadmium plated for corrosion protection. These bearings can be re-lubricated thru the inner ring bore. When mounting, care should be taken to properly support the end plates to eliminate the possibility of bearing separation due to thrust loads. These bearings are dimensionally interchangeable with the corresponding YAD and YAS Series. Smith Bearing® has been a leader in the design and manufacture of specialized bearings for the unique requirements of jet engines. We have kept pace with the ever increasing demands for anti-friction bearings to operate at higher temperatures. Thrust reversers, afterburners, and divergent nozzles are some of the areas in which Smith Bearing® Bearings are currently functioning. Contact our engineering department for recommendations and design assistance. Military Qualifications The products listed meet the military requirements of Mil-B-3990 (SAE AS 39901) Smith Aircraft Bearings are marked with the bearing designation including bearing type code. Many of these bearings are supplied pre-lubricated to meet the OEM's special requirements. When ordering, attention must be paid to the original manufacturers parts list requirements so that proper identification can be provided. Federal Aviation Administration Parts Manufacturing Approval FAA PMA Smith manufactures bearings to meet the provisions of the Federal Aviation Regulations (FAR) for Parts Manufacturing Approval (PMA). Smith Bearing® maintains an active list identifying all of our FAA PMA parts and where they are applicable. This list is available upon request. YAD (MS24465) & YAS (MS24466) YAD and YAS Series Yoke Type bearings are dimensionally similar to the YAF and YAT Series. These bearings were designed for track roller applications where the outer race of the bearing is unsupported. They will handle heavy rolling or oscillating motion. The outer race is hard-chrome plated and all other exposed surfaces are cadmium plated for corrosion protection. The bearing is held together using a swedged ring inserted around the inside of the end washers. These bearings are generally considered for replacement in existing applications. For new applications and current designs use the YAF and YAT Series. YAG (MS24461) YAG Series Yoke Type bearings were designed for applications where the bearing is mounted inside the housing. These bearings handle slow rotating or oscillating motions. All external surfaces except the bore are cadmium plated for corrosion protection. The bearing is held together using a swedged ring inserted around the inside of the end washer. HRS (MS21432) & CHRS (MS21447) HRS and CHRS Series Stud Type bearings are of non-separable construction and are used in applications involving high-static loads or oscillating motion. The HRS-Series - straight cylindrical outer race and the CHRS-Series - crowned outer race were designed for airframe usage in flap tracks, canopies, and landing gear. When misalignment is a concern, the CHRS (crowned) Series is preferred. The outer races are hard-chrome plated and all other exposed surfaces are cadmium plated for corrosion protection.

Aerospace Bearings Load Ratings Aircraft Static Capacity (ASC) is the maximum load which can be placed on a housing mounted needle roller bearing without seriously brinelling the raceways (approx. 0.0001 inch deep) or deforming the rolling elements. Unsealed aircraft bearings can be operated at temperatures up to 400 ˚F provided that suitable lubrication is present. Higher temperature exposure will result in loss of capacity. The operating temperature for sealed bearings is limited to 250 ˚F due to the seal material. Limit Load Rating is the maximum static load that can be applied without...