Posts Tagged ‘spherical roller bearing’

Timken Primary Processes / Thermal Treatment Processes

Wednesday, July 6th, 2011

PRIMARY PROCESSES

HOT ROLLING

Hot rolled tubing has a surface finish comparable to hot rolled bars, plates or sheets of equal thickness. Light mill oxide covers both the outside and inside surfaces. Hot rolled tubing can be produced to outside diameter and wall dimensions with stated tolerances.

When a quotation for this highly specialized product is requested, we work closely with the customer to gain as much knowledge as possible about the end use. This enables us to apply materials with optimum dimensions to reduce costs.

COLD DRAWING

Cold drawn tubing is produced from hot rolled tubes that have been carefully inspected and properly surface-conditioned. Cold drawing consists of pulling a tube through a die and over a mandrel, reducing the diameter and wall thickness. Tubing is cold drawn for one or more of the following reasons: closer dimensional accuracy, better surface finish, smaller sizes than can be hot rolled, or to achieve certain mechanical properties. Cold working also imparts higher strength to the tubing and tends to improve machinability of carbon and lean-alloy steel.

ROTOROLLING®(Cold Pilgered)

Rotorolled tubing is produced from hot rolled tube shells that are conditioned for further reducing. Rotorolled tubes are produced on a machine designed to make large reductions of the cross-sectional area in one pass of the tube. The machine operates by cold swaging the tube between semicircular dies containing tapering grooves. The dies rock back and forth while the tube is advanced and rotated between rocking cycles over a long tapering mandrel. The developed contour of the die grooves forms a tapering circular pass that ends in a constant-diameter ironing section that establishes the OD of the finished tube.

Rotorolled tubing is a premium product with a surface condition superior to those obtained by cold drawing. Machinability is excellent. Dimensional tolerances are very uniform. Our ability to obtain large reduction ratios allows superior mechanical properties to be achieved.

Wall thickness of up to one-third of the outside diameter can be produced.

  

ROUGH TURNING                           

 Turned tubing is produced by machining the outside surface of the hot rolled tubing. This process removes surface defects and decarburization from the outside, but the inside diameter surface retains the hot rolled finish. This is accomplished in a machine where the tools are mounted in a ring and rotated around the tube. The only motion of the tube is lateral, through the ring and past the rotating tools. Turned tubing is used extensively in automatic screw machines for manufacture into ball and roller bearing races and for special applications where advantages can be taken of the close outside tolerance or clean outside surface. Any hot rolled size up to 8 inches OD can be rough turned. Surface finish approaches 125 RMS or better.

 

THERMAL TREATMENT PROCESSES

 ANNEALING

Annealing is heating uniformly to a temperature within or above the critical range and cooling at a controlled rate to a temperature under the critical range. This treatment is used to produce a definite microstructure, usually one designed for best machinability. It is also used to remove stresses; induce softness; and alter ductility, toughness or other mechanical properties.

HOT BED COOLING

This is the standard process of air cooling the tubing immediately following piercing on a special table or hot bed that continuously advances the tubing as additional tubes are finished. Tubing that is hot bed cooled may require additional thermal treatment to obtain optimum machinability or required mechanical properties.

MILL ANNEALING

Mill annealing is a controlled cooling of the tubing immediately following piercing which produces – in some low and medium carbon alloy grades – the optimum hardness and microstructure for machinability.

NORMALIZING

In this process, steel is heated uniformly to a temperature at least 99° F (37° C) above the critical range and cooling in air to room temperature. This treatment produces a recrystallization and refinement of the grain structure and gives the product uniformity in hardness and structure.

PROCESS TEMPERING

Process tempering is performed to improve subsequent fabrication of the material (machining, cold working, etc.). See Tempering.

QUENCHING (QUENCH HARDENING)

This processes heats steel uniformly to a temperature above the critical range and cools it rapidly in a liquid medium.

SPHEROIDIZE ANNEALING

This special type of annealing requires an extremely long cycle. Spheroidize annealing is used to produce a globular condition of the carbide and maximum softness for best machinability in some analyses or to maximize cold formability.

STRESS FREE

This designates tubing that has been hot rotary straightened. Minimal straightening stresses develop in hot rotary straightening, so stress relief tempering is not needed. Cold rotary straightening and stress relieving can substitute for hot rotary straightening.

STRESS RELIEVING

Stress relieving is a final thermal treatment used when stress-free material is desired. Its purpose is to restore elastic properties and minimize distortion on subsequent machining or hardening operations. This treatment is usually applied on material that has been heat treated (quenched and tempered). Normal practice is to heat to a temperature 99° F (37° C) lower than the tempering temperature used to establish mechanical properties and hardness.

TEMPERING

Tempering heats uniformly to a temperature under the critical range, holding at that temperature for a designated period of time and cooling in air. This treatment is used to produce one or more of the following end results:

  • To soften material for later machining or cold working. Also referred to as a Process Temper.
  • To improve ductility and relieve stresses resulting from prior treatment or cold working.
  • To produce the desired mechanical properties or structure in the second step of a double

Timken — Corporate overview

Thursday, March 31st, 2011

History of The Timken Company

For more than 100 years, Timken has focused on value creation for diverse industries and market segments. We deliver a variety of friction management and power transmission solutions for applications ranging from aircraft and automobiles to mining equipment and medical instruments.  We’ve grown considerably since our founding in 1899, but solving customer problems is still at the core of our business, just like it was when founder Henry Timken patented a tapered roller bearing design that made life easier for freight wagon operators and their mules.

The Beginning

Henry Timken, a St. Louis carriage maker, recognized that heavy freight wagons had a hard time making sharp turns. To solve the problem, he applied a tapered roller bearing design that could handle both radial (weight) and thrust (cornering force) loads. There were several customer benefits. First, the application ran more smoothly, reducing repair and replacement costs. In some cases, the bearings improved wagon performance so much that fewer mules were required to pull them. Finally, better cornering meant less chance of losing a load of goods. Always focused on customer benefit, Henry quickly realized that the tapered roller bearing could improve product performance in many other applications as well. He and his sons, H.H. and William Timken, quickly founded The Timken Roller Bearing and Axle Company and began building the business into what it is today.

Corporate Overview 

Wherever there is motion, you’ll find Timken at work. Timken is one of the world’s leading producers of highly engineered antifriction bearings and related products and services and alloy steel and components. We help create, transfer and control power, putting our friction management and power transmission technologies to work across a broad industry spectrum.

Timken has operations in 27 countries on six continents, and our team of 20,000 employees is dedicated to improving our customers’ performance in a variety of applications.

Oh oh .. Have run into a road block …..

Thursday, January 20th, 2011

Help — I’ve fallen and can’t get up. 

Now that I’ve used the allotment of cliches where do I go from here.  Even the best of us run into brain blocks, and I’m no exception.  I have been doing research, and working hard learning the background information for the new website, www.bearingsinc.net that is soon to be launched.  I know “you’ve heard this all before”, but be assured that it is close to launch date, and it will change consistently once it is launched.  We want to make it better and easier for you to use. 

Right now, I have uploaded “most” of our Timken line; which is our biggest line.  This consists of both ball and roller bearings.  Ball bearings consisting of Angular contact, Wide inner ring, and Housed units. Roller bearings consisting of the Tapered Roller Bearings Cups, cones, and sets that Timken has always been famous for. 

I have also uploaded our Koyo Ball bearing line, which could offer some of the same parts as Timken.  We also have SKF-Chicago Rawhide currently uploaded which offers seals, and speedi sleeves.

In my plans, and my next uploading attempts consist of Koyo NEEDLE bearing line, and MBL (Mitsuboshi) belts.  These will cover quite a bit of items we can currently offer, but you need to watch the sight because once it’s launched, I will be configuring other databases to upload.  This way it will keep the sight changing, and interesting. 

New items = new choices = more options

While I’m not making any promises of a launch date; keep in touch and help us celebrate our launch when all of our hard work has finally come to an end.

Design and Characteristics of Ball and Roller Bearings

Tuesday, August 17th, 2010
NTN Catalogue – Part 2 of 2

Continued from Part 1 of August 12, 2010

DOUBLE ROW SELF-ALIGNING BALL BEARINGS utilize an inner ring with two rows of balls, in two deep raceways; and an outer ring with a single spherical raceway.  In this way, the inner and outer rings can be misaligned relative to each other.  The resulting affect is a comparatively large angle imposing moment loads upon the balls. 

The boundary dimensions of the 1200 and 1300 series are the same as the 6200 and 6300 single row deep groove bearings.

CYLNDRICAL ROLLER BEARINGS have rollers which are essentially cylindrical in shape.  This provides 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 allows the inner ring to have axial movement relative to the outer ring (except the NH type).  This is especially important when accommodating thermal expansion when both rings must be press fitted. 

In this series, the NJ, NF, and NH types can carry light or intermittent thrust loads.  The bearings utilizing machined bronze cages are suitable for high speed operation.

The NN3000 and NN3000K series are available in high precision tolerances and are well suited for use in machine tool spindles.

TAPERED ROLLER BEARINGS utilize conical rollers and raceways arranged so that the rollers and raceways meet at a common apex.    The rollers are guided by contact between the large end of the roller and a rib on the inner ring.  This provides high capacity for radial and single thrust loads.

SPHERICAL ROLLER BEARINGS have two rows of rollers in separate raceways which allows the bearing to compensate for angular errors.  They have large radial and thrust load capacity for heavy shock and impact loads, suitable for heavy industrial equipment.

DUPLEX BEARINGS use a set of two on a common shaft with the inner and outer rings clamped solidly together.  They are used to gain axial shaft control, rigity and extra capacity.

There are three fundamental combinations n duplex bearings: face to face (DF); back to back (DB); and tandem (DT).

The back to back mounting (DB) has the load lines through the balls converging toward the outside of the bearing.  This arrangement is preferred when the pair of bearings is to resist moment loading.

The face to face mounting (DF) has the load lines through the balls converging  towards the axis of the bearing.  This arrangement is less sensitive to slight angular errors in mounting of the bearings.

The tandem mounting (DT) is arranged so that the load lines through the balls are parallel to each other.  This mounting is used when it is desired to divide a heavy thrust load between the two bearings.  Since this mounting carries thrust load in one direction only, a third bearing should be provided to take thrust load in the reverse direction.

SINGLE DIRECTION THRUST BALL BEARINGS consist of two washers having ball grooves ground into their adjacent faces with balls and cages mounted between these grooves.  They are normally equipped with either pressed or machined cages and are suitable for carrying thrust loads at moderate speeds.

DOUBLE DIRECTION ANGULAR CONTACT THRUST BALL BEARINGS are back to back duplex bearings with a larger contact angle than that of normal angular contact ball bearings. 

These bearings have been recently developed, and are primarily designed as thrust bearings for machine tools.  They utilize machined brass cages. 

SPHERICAL ROLLER THRUST BEARINGS are similar to double row spherical roller bearings, but have a greater contact angle.  They are guided by ground flanges on the inner ring and operate against the spherical raceway in the outer ring.  The contact angle is approximately 45⁰.  Machined cages are normally used and oil lubrication is recommended.