High lead ball screws run quietly
Featuring a 3:1 lead/diameter ratio for linear speed as high as 3 m/second and a low rotary speed, these ball screws come in shaft diameters from 15 to 25 mm and lead sizes from 40 to 80 mm. A special endcap recirculation system, and a ball groove design that NSK describes as unique, make operation quiet and smooth. Using a Gothic arch thread groove design improves efficiency and decreases torque requirements, relative to conventional ball screw designs. To provide the opportunity to convert axial force to rotary torque with an air or oil cylinder, the units feature a lead angle of 45 degrees. Ball screws are available in C5 and C7 accuracies. NSK Corp., Precision Products Div., (800) 255-4773.
More sophisticated driveshaft assemblies
Complete redesign of Spicer Driveshaft's 10 Series product has resulted in the introduction of the Spicer Life SeriesTM heavy-duty driveline assemblies. Production of assemblies for class 7 and 8 trucks begins in July, while mid-range and line-haul class 6, 7, and 8 assemblies will go into full production this year. "We felt that yesterday's technologies weren't sophisticated enough for today's trucks," says Bob Fesenmyer, general manager for Spicer Driveshaft. In the new designs, a plastic boot seals the slip assembly from outside contaminants for life. Also, the sliding components of the slip spine assembly incorporate a tube yoke shaft that mates to an integral driveshaft sleeve. The new integral tube sleeve and yoke shaft design provides lighter weight with larger-diameter, close-tolerance involute splines, enhancing strength and stiffness. Spicer Driveshaft Div., Dana Corp. (419) 866-2600.
Concentric drives use tapered roller bearings
New UltramaxTM concentric drives, intended for use on conveyors and other industrial applications, reportedly offer users low maintenance requirements and improved durability. "The use of tapered roller bearings instead of ball bearings throughout the drives is probably the biggest design change" in Ultramax drives, says Product Manager Rick Lynch of Falk Corp. All gearing in the drives is either carburized and ground or induction-hardened. Ultramax drives come in ten sizes with torque output ranging from 2,500 lb-inches to 600,000 lb-inches. The drives' torque outputs represent an increase of 50 to 60% relative to previous designs in each size. Falk Corp., (800) 545-5215.
A gearhead intended for servo motors
The StealthTM line of planetary gearheads uses plasma-nitrided gears hardened to 65RC. These gears, made to precision levels exceeding AGMA12 provide excellent wear resistance. The all-helical planetary gear heads offer 30 to 40% more torque in the same package as a simple spur planetary. Also, the gearheads generate 10 dB less noise than comparable spur planetary systems. A patent-pending design called ServoMountTM makes the new Stealth gearheads easier to use by eliminating the problems involved in mounting a precision gearhead to a motor. Peak output torques of the four models now available range from 3,053 lb-inches to 30,002 lb-inches. Bayside Controls Inc., (516) 484-5353.
Coupling meets servomotors' needs
Designed for use with digital ac, dc synchronous, and stepper servomotors, the ServoClass coupling offers low inertia, zero backlash, and torsional stiffness. It can also be used to couple encoders or resolvers to servomotors. Presently available in six standard models, the couplings are rated for operating torques from 1 Nm for the Model SC 010 to 25 Nm for the SC 050. Torsional stiffness for the six ranges from 170 Nm/radian to 20,000 Nm/radian. Overall coupling length ranges from 27.5 mm for the SC 010 to 61 mm for the SC 050. Zero-Max Inc., (612) 546-4300.
Helicopter driveshaft needs no lube
Flight mechanisms on helicopters can generate misalignment between the vehicle's engine and transmission. KAflex driveshafts are mechanical drive couplings that require neither lubrication nor seals. Flexible rectangular frames enable them to accommodate angular misalignment and length change, while transmitting power. End-hubs connect the assembly to driver and driven load. Because all components are rigidly connected and all torque transmitted through stiff frames, no windup or backlash can occur. A fail-safe feature enables the coupling to transmit power even if a load-carrying member fails. Kamatics Corp., 860-243-9704.
Ball bearing units for air handling
Featuring ground and honed raceways and high-precision balls, SKF air handling ball bearing units are prelubricated. Grease used in the units is selected for air-handling applications and helps ensure both quiet operation and long life. Closely controlled air-handling alignment torque improves system reliability in the units to allow operating misalignment. Also, 120-degree set screw spacing minimizes inner ring distortion for less vibration and better sealing. Patrick Carey, an application engineer with the fluid Machinery segment of SKF USA, says the bearing units are mostly used in ventilating equipment. SKF USA Inc., 800-881-4SKF.
Bearings offer longer life
Timken's new XLP900TM roller bearings, named to reflect extended life practice, feature a special process developed by The Timken Company to provide as much as a 30% life extension, when compared to the company's older P900TM bearings. "Timken XLP 900 bearings capitalize on everything the company has learned about the effects that improvements to bearing material, surface finish and raceway profile have on system performance," says Gerald P. Fox, chief engineer, customer engineering, North American general industrial. The Timken Company, 330-471-3825.
Joined drive belt beats shock loads
Green Stripe(R) PowerBand(R) belt reportedly provides maintenance-free service on heavy-duty engine drives subject to violent pulses and extreme shock loads. To form the belt, designers join two or more Gates premium V-belts with a permanent, high-strength tie band. The product is claimed to bend over pulleys as easily as multiple V-belts, but the tie band increases stability to hold the belt on the drive and prevent it from turning over. Applications especially suited for this belt include high-load, high-horsepower drives that abruptly start and stop. A thinner profile and variable notching pattern produce cooler, quieter operation and reduce cracking. Gates Rubber Co., [email protected]