A constant velocity universal joint includes an inner ring and an outer ring. A cage is disposed between an outer spherical surface of the inner ring and an inner spherical surface of the outer ring, and has windows in which respective balls are received. The cage has ball contact surface areas with which the balls come into contact, and includes soft portions that are lower in hardness than the ball contact surface areas. The soft portions are formed by local heat treatment at portions of the windows that are kept out of contact with the balls or surface portions around the windows.

A Plain bearing having an outer ring and an inner ring, the outer ring and the inner ring providing respectively an inner surface and an outer surface intended to cooperate with each other for the relative movement of the outer and inner rings, the inner surface of the outer ring and the outer surface of the inner ring each including a coating including at least one layer. The hardness of the coating on the inner surface of the outer ring is less than the hardness of the outer ring, and the hardness of the coating on the outer surface of the inner ring is greater than the hardness of the inner ring.

The present invention discloses a shaft-tube joint structure of a carbon fiber reinforced plastic (CFRP) drive shaft. The shaft-tube joint structure includes a hollow shaft tube, a plurality of first rectangular teeth being uniformly and circumferentially arranged at both ends of the hollow shaft tube; two shaft-tube joints which are respectively fixed at two ends of the hollow shaft tube, the thickness of the shaft-tube joint being smaller than that of the hollow shaft tube, and an inner wall of the shaft-tube joint being smoothly connected to an inner wall of the hollow shaft tube; and a universal joint, an end thereof being tubular, a plurality of second rectangular teeth being uniformly and circumferentially arranged, the universal joint being matched with and sleeving the outer wall of the shaft-tube joint, and the second rectangular teeth being meshed with the first rectangular teeth.

A method for controlling carbide network in a bearing steel wire rod by controlling cooling and rolling, comprises the following steps: rapidly rolling a bar to a wire rod and spinning it into a loose coil, controlling the rolling temperature at 780° C.-880° C.; and the spinning temperature at 750° C.-850° C.; carrying out on-line controlling cooling of continuous loose coils using EDC water bath austempering cooling process, controlling the cooling rate at 2.0° C./s-10° C./s, and controlling the final cooling temperature within 620-630° C.; after EDC water bath austempering cooling, using slow cooling under a cover, and the temperature is controlled to be 400° C.-500° C. when being removed out of the cover; after slow cooling, collecting coils, and cooling in air to the room temperature.

A shaft for a gas turbine engine includes an inner contour with a stiffening rib that defines a stiffened wall thickness related to a nominal wall thickness according to a ratio between about 1.125-2.1.

A sliding member includes an overlay layer made of a resin on a side of a sliding surface of a bearing alloy layer. When a valley void volume Vvv (μm.sup.3/μm.sup.2) in the sliding surface of the overlay layer is defined as Vv1, Vv1 is in a range of 0.015≤Vv1≤0.200.

A bar portion is formed so that an outer circumferential surface on a tip portion side is located on an inner diameter side with respect to an outer circumferential surface of a main portion. On an inner diameter side of a cage, lightened portions obtained by notching in an axial direction from an axial side surface of the main portion are formed separately at positions of the respective bar portions in a circumferential direction. Each lighting portion is formed separately from a surface of a pocket and an axially outer surface of the bar portion formed between a pair of claw portions. An axial dimension T1 of a wall portion formed between an axially outer surface of the bar portion and an inner wall surface of the lightened portion is greater than an axial dimension T2 of the main portion on a bottom portion of the pocket.

A rolling bearing having an outer ring, an inner ring, and at least one row of rolling elements disposed between two raceways of the outer and inner rings. Furthermore, the raceway of the outer ring and/or the raceway of the inner ring at least partially provide a coating based on chromium nitride, the rolling elements at least partially include a coating based on carbon.

A system for an unmanned aerial vehicle can include an altitude control system, which further includes a compressor assembly, a valve assembly, and an electronics assembly. The compressor assembly may include a driveshaft and a bearing assembly configured to rotate the driveshaft. The driveshaft may be formed from a first material and a compressor housing may be formed from a second material. The first and second materials may have different rates of thermal expansion. A dynamic preloading mechanism, such as a flexible plate, may be provided within the compressor assembly to exert a preloading force on the bearing assembly. Throughout the duration of the flight of the unmanned aerial vehicle, the preloading mechanism can continually compensate for differences in rates of thermal expansion between the first and second materials throughout.

A hydrodynamic bearing in the form of a flex pad bearing includes configurations structured to change a bearing characteristic. One form of the bearing includes a nonlinear back wall that includes a circular arc and a transition, where the back wall extends radially outward of a ligament. The bearing can include an opening for the deposit of a weighted mass, wherein the opening can threadingly receive a threaded weighted mass. In one form a sidewall that includes the back wall segment can have an average outer radius which determines a thickness of the flex pads.