Archive for August, 2013

Triple-Sealed Bearings for Bearing Units

Friday, August 30th, 2013

What are the main features of triple-sealed bearings?  Here you go:

  • Better dust-proofing and waterproofing pave way for a longer bearing life.Triple-sealed bearings come with a secure bearing seal with three lips. This unique seal has trusty dust-proofing and waterproofing abilities, much greater than those of normal bearings utilized in bearing units. This guarantees a longer bearing lifespan even when they are constantly exposed to heavy airborne dust and splashes of foul water.
  • They help in cutting back on maintenance cost.A bearing that lasts even longer than a standard bearing unit configurations would mean longer maintenance intervals, immensely lessened maintenance costs, as well as more machinery availability.
  • The price of the bearing unit drops and adds up to more compact machinery.The triple-sealed bearing unit is a replacement for traditional covered bearing units in particular operating situations, thus dramatically reducing the cost of bearing units. Furthermore, if the cover is not necessary, the machinery could be more compact.
  • Secure balled setscrewThe triple-sealed bearing from NTN is mounted on a shaft with NTN’s unique balled setscrew, which has an embedded ball right in the tip. As compared to the knurled cup point or cup-point setscrews, the balled setscrew comes with more resistance to loosening, considering it doesn’t readily loosen because of vibration or impact.
  • InterchangeabilityThe triple-sealed bearing unit follows the JIS (Japanese Industrial Standard) for UC-type bearings. Not only is it ready to use as a relubricable bearing, but it can also be a replacement of the traditional bearing units.

Perhaps this is the solution you need in your application.  Visit our main website or give us a call at 1-800-457-3329 to discuss.

 

Specifics In Regards To Super-precision Bearings

Friday, August 23rd, 2013

Machine tools and other precision applications call for some tiptop bearing performance. Outstanding speed capability, high levels of running accuracy, high system rigidity, low heat generation, along with low noise and vibration levels are included in the challenges, just to name a few.

Rolling bearings for general industrial applications only does partial fulfillment of the said requirements. That being said, makers of bearings these day come up with a wide array of super-precision bearings.

The advantages vary in accordance with the bearing series and applications, but  they involve high speed as well as load carrying capacity, long bearing service lifespan, long maintenance intervals on top of low energy consumption.

The usual applications for super-precision bearings include:

  • metal cutting and woodworking machinery spindles
  • other machine spindles (e.g. balancing machines)
  • high speed rolling mills
  • printing machinery
  • precision ball screws
  • live centers
  • high speed turbochargers
  • vacuum pumps
  • racing cars
  • boat gyrostabilizers
  • machine components for the semiconductor industry

Precision bearings are built to come with high accuracy, high rotational speed, and high rigidity needed for particularly demanding usages.  That said, go ahead and look for super precision ball bearings that give the highest level of accuracy, backed up by production capability, the most up-to-date equipment and extensive manufacturing expertise, and those that promise to give the same rigorous quality control procedures at every stage of their production process.

Go for super precision ball bearings that can meet these requirements:

  • Great accuracy
  • High rotational speed
  • Quiet and smooth running
  • Minimum friction and heat generation
  • Controlled rigidity

 

About Cylindrical Roller Bearings

Friday, August 16th, 2013

Cylindrical roller bearings come with rollers that give a modified line contact with the cylindrical inner and outer ring raceways, while the rollers are guided by ground ribs on either the inner or outer ring.

The cylindrical shape makes it possible for the the inner ring to have axial movement that is relative to the outer ring. This becomes particularly significant when dealing with thermal expansion, in which two of the rings should be press-fitted.

In this particular bearing type, the cylindrical rollers are in linear contact with the raceways. They possess a high radial load capacity and they’re ideal for high speeds.

There is a variety of types designated as NU, NJ, NUP, N, NF (for single-row bearings), NNU, and NN (for double-row bearings in accordance with the design or absence of side ribs). The outer and inner rings of every type is separable.

There are some cylindrical roller bearings that come with no ribs on both the inner and outer ring. That being said, the rings are able to move axially relative to one another. They could be used as free-end bearings.

Cylindrical roller bearings, where either the inner or outer rings possesses two ribs, and the other ring possesses one, can take some axial load in one direction. Double-row cylindrical roller bearings have high radial rigidity, and they’re mainly used for precision machine tools.

Generally, pressed steel or machined brass cages are utilized, but there are cases in which molded polyamide cages are employed.

Depending on the existence of ribs on their rings, Cylindrical Roller Bearings are categorized in these types:

Types NU, N, NNU, and NN are ideal for free-end bearings. Types NJ and NF are able to sustain limited axial loads in one direction. And you can use types NH and NUP as fixed-end bearings.

NH-type cylindrical roller bearings have the NJ-type cylindrical roller bearings and HJ-type L-shaped thrust collars. The inner ring loose rib of an NUP-type cylindrical roller bearing must be mounted in order for the marked side to be on the outside.

How to Change Wheel Bearings

Friday, August 9th, 2013

A car’s suspension includes wheel bearings. For the most part, they are found in the wheel’s hub, rotor or brake drum. They assist the wheel in rotating as the vehicle moves. In the event there’s whirring or humming sound as you drive, or if your ABS light turns on, it’s high time you replaced your old bearings with brand new ones. Wheel bearings are, by all means, a necessary element of a car, but you can do the replacement yourself. Here are the steps:

  1. Park your car on a level surface and be sure the parking brake is up.
  2. If you are trying to fix a front wheel bearing, put a wheel cock behind the rear. If you’re working on a rear wheel, place a wheel cock behind a front tire. Break loose the lug nuts of the wheel you are repairing using a socket and a breaking bar.
  3. Use a jack to lift the wheel. See to it that the vehicle is on the jack before you even attempt to lift. When the wheel is off the ground, you may then take off the lug nuts and the wheel.
  4. Take the bolts off with the use of a socket and a ratchet. Then, with the use of a screwdriver, remove the caliper. See to it that the caliper does not dangle and hit the brake hose.
  5. In the event the rotor gets stuck, you can hit it loose using a rubber mallet. However, you may incur damage to the rotor. That said, the best way to go about it is using a mallet only if you don’t plan on reusing the same rotor.
  6. Loosen the wheel bearing bolts with the use of a socket and a breaking bar.
  7. Sand off rust or corrosion that you notice surrounding the knuckle. Be meticulous working around the drive shaft spindle so you get rid of all the rust or corrosion. The knuckle must be thoroughly cleaned before installing the new wheel bearing.
  8. Install a new bearing on the knuckle. Push the bearing as far as possible, making it a point that it’s correctly lined up. When it is far enough, change the assembly bolts. Working on the bolts a little at a time will guarantee that the assembly does not move or bring about damage.
  9. Change the lug nuts as well as the tire. After having installed the new bearing, you may then change the lug nuts and tire. See to it that the lug nuts are tightened as much as possible before you lower your vehicle using the jack.

Mechanical Tools for Mounting and Dismounting

Friday, August 2nd, 2013

Mounting
Nearly 16% of all premature bearing failures are brought about by bad fitting or usage of incorrect mounting methods. Individual applications could call for mechanical, heat or hydraulic mounting techniques for proper and effective bearing mounting. Choosing the right mounting method for your application aids in prolonging the bearing’s life span and cuts back on costs caused by premature bearing failure, and potential damage to the application.

Mounting bearings in a cold condition
For the most part, small and medium size bearings are cold mounted. Usually, the bearing is mounted with the use of a hammer along with a length of old pipe. Such technique can cause forces to be transmitted via the rolling elements, bringing about damage to the raceways. Some fitting tool aids in avoiding bearing damage by means of applying the forces to the bearing ring with the interference fit.

Dismounting
When you dismount bearings, you should be extra cautious not to damage other machine components, likes the shaft or housing, since damage could compromise the machine’s efficiency and life span. In some cases, bearings are dismounted to maintain or replace other components of the machine. Such bearings are typically re-used. Choosing the right dismounting techniques and tools is important in cutting the risk of injuries and lowering the chances of incurring damage to the bearing, so it can be used again. Individual applications could need mechanical, heat or hydraulic dismounting techniques and tools to pave way for safe, proper and effective bearing dismounting.

Mechanical dismounting
Selecting the correct puller for the job is crucial. The puller type, as well as its maximum withdrawal capacity, are vital for completing any dismounting job safely and conveniently. Puller overload can cause breakage of the puller’s arms and/or beam, so it must be avoided. Such breakage could incur damage to the bearing or shaft and can bring about accidents. Generally speaking, it’s best to opt for a three-arm puller instead of a two-arm puller, considering the three-arm puller is more stable. As much as you can, apply the withdrawal force to the ring with the interference fit.