Spherical bearing boasts power density
Leveraging their expertise in bearing design, engineers at SKF have recently developed a new generation of spherical bearings, called Explorer, that they say sets a whole new standard for bearing performance. In fact, test data confirms that bearing life is 3X better than standard bearings. The secret? A higher quality steel and modifications to the heat treatment process, as well as a change to the internal design that helps to distribute stress more uniformly. These design enhancements have also led to higher power density and higher reliability.
Lube-free recirculating linear bearing
A recirculating linear bearing from Schneeberger is being described as lubrication-free. The secret is in the ball bearing design. Load carrying ball bearings are made from ceramic. Smaller-diameter balls made of Teflon(R)are used to separate them, reducing the rotation friction when balls come into contact with one another. Called the SKC, the bearing is available with 3-mm ceramic balls bearings (SKC3075) and 6-mm ceramic ball bearings (SKC6100).
Spherical bearings rated to 250C
Two years of development may be about to pay off for NTN Bearings, who has just introduced a new series of self-aligning spherical roller bearings, rated for use up to 250C. According to Engineer John Husemann, a slightly different composition of steel gives the bearing a higher hardness, and allows it to maintain that hardness even at higher temperatures. Typical bearing steels are rated to 220C. And although the higher operating temperature is a plus, Husemann points out that the bearing outperforms standard bearings even at lower temperatures. At room temperature under heavy-load test conditions, a standard bearing lasted 122 hours, while the LH bearing lasted 432 hours, or a 3.5X improvement, says Husemann. Likewise, the bearing showed 2.5X resistance to wear and 2.0X better crack resistance than a bearing fabricated out of standard bearing steel. The bearing is currently available in sizes up to a 420-mm diameter.
Linear bearings offer integrated solution
"The aim in developing this product was to try and make life a little easier for mechanical design engineers," explains Mechanical Engineer Rich Goldy, describing the rationale for Pacific Bearing's new integrated linear motion product. It consists of the company's Dolphin linear guide, drive mechanism (lead screw, ball screw, or cylinder), motor, and controller (from API). Since the controller part in particular can be confusing for mechanical design engineers, Pacific Bearing engineers researched the market thoroughly to find a controller to team up with that they feel is among the easiest to program. "After 5 to 10 minutes of training, a design engineer is ready to point and clicks-he or she doesn't have to be a controls engineer to figure it out," says Goldy.
Ready-mount needle bearings
One limitation of needle bearings has been the fact that it's impossible to mount them directly into a thin sheet of steel without using some kind of rigid, accurately-machined housing block to retain the bearing. Not anymore. Engineers from Spyraflo and Torrington have teamed up to develop a new series of ready-mount needle roller bearings called, not surprisingly, ReadyMount. Engineers were able to patent the design, says Torrington's Mitch Busell, manager of new product development, which combines a rolling element bearing with a self-clinching feature. The design allows the bearing to be mounted in a thin-section (0.04 inch) chassis. The product is available with a self-aligning feature, allowing it to swivel plus or minus 5 degrees to accommodate any misalignment of mounting holes.
Bearing handles limited rotation
Once the patents ran out on the C-Flex bearing, design engineers didn't just rest on their laurels. "We've made several improvements on the original design, most notably in changing the design of the internal structure so that we can actually operate at higher temperatures and heavier loads," says Product Engineer Wayne Smith. The bearing, which is considered to be in the same class as bushings because it has no rollers or balls, is of a rather unique design: It uses flat-crossed springs in a split cylindrical housing. Bending of these internal spring beams facilitates rotation. Working within tight geometric constraints, explains Smith, engineers were able to increase the length of the springs, thereby reducing the bending stress on them and resulting in a higher load capacity (up to 1,600 lbs). "It was a tricky design problem, because we could not reduce the size of the external spring structure," says Smith. The bearings, which are designed for limited rotation angle ( plus or minus 15 degrees ), are available in standard sizes ranging from 1/8 to 1 inch diameter.