Posts Tagged ‘bearings’

Why and when to develop an equivalent for leaded bearing materials?

Tuesday, August 17th, 2010

bearingsIn the July 2010 issue of RET-Monitor, keyword: bearings, I wrote about lead-free bearings and possible engineering concerns surrounding their introduction. Extending the search for the reasons behind why the substitute for leaded bearing materials is not yet embraced by the race engineers led to a short interview with a leading supplier of competition bearing shells.

In addition to possible sensitivity issues concerning roundness (shape and steps in the circumference of the bearing bore) and the lower conformability and embedability of the unleaded, harder materials, the temperature inside the bearing is considered to be of major importance in the selection of the bearing material.

Read more…

Lead free bearing(s) fit

Friday, July 2nd, 2010

bearingsIn another article in this issue of RET-Monitor, I have given what I hope is an insight into crankcase main bearing split design (keyword: heads-blocks). Background is the accuracy of the main bearing split line geometry, primarily focused on the roundness of a main bearing bore.

Since the crankshaft system does not directly rotate in the bearing bore, we will look at the bearing shells in between. As John Coxon wrote in the May 2010 issue of Race Engine Technology

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Bearing the load

Thursday, May 13th, 2010

bearingsIn most motorsport applications, bearings have had to cope with increasing loads as the requirements for higher performance of engine, gearbox and suspension components continues to increase.

Recalling his days at Tyrrell, Renault’s Formula One chief designer Tim Densham says, “Normally you would just open the SKF book and pick out standard bearings for most of the shafts.” Things have moved on somewhat from those days, although even then some companies did make Read more…

Getting the best from rolling element bearings

Tuesday, March 30th, 2010

bearingsOnce problems with rolling element bearing reliability have been chased in NASCAR Sprint Cup Series competition, is it worth trying to gain performance improvements?

The rolling element bearing does consume some power. While mechanical losses are worth a little more than you might think, there are actually two gains made for every reduction of mechanical loss implemented. Read more…

Rolling contact bearings

Tuesday, February 16th, 2010

bearingsThe terms rolling contact bearing, anti friction bearing and rolling element bearing are used to describe that class of bearing in which the main load is transferred through elements in rolling contact with each other. Friction in a rolling element bearing is present, but it is negligible when compared to the starting friction of a journal type bearing. The load, bearing speed and the viscosity of the lubrication all affect the friction within the bearing. Although it is not technically correct to refer to this type of bearing as anti friction, it is a name that is in constant use. Read more…

Bi-metal Journal bearings: Materials and construction

Thursday, January 21st, 2010

bearingsTraditional main bearing construction is based on a three-layer bearing made of a steel backing, a hard mid layer and a thin overlay of a soft material.

The bi-metal bearing is constructed of only two layers, consisting of a steel backing with an inlay of an aluminium alloy. Typical bearing materials used in the construction of bi-metal bearings are a combination of the following materials: Tin, silicon, lead, copper and aluminium. The bearing Read more…

Tri-metal Journal bearings: materials and construction

Saturday, December 19th, 2009

bearingsTraditional journal bearings for internal combustion are of the tri-metal type. This type of bearing consists of a steel backing, a hard middle layer and a soft top layer. Typical soft bearing materials are: lead, tin, zinc, or alloys of these metals while typical hard bearing materials are: Aluminium-tin; lead-bronze; copper-lead. The soft top could comprise of three layers, providing five metal layers.

Journal bearings operate between the extremes of no lubrication on the one hand, to thick-film lubrication on the other. Therefore, bearing material must possess Read more…

FATIGUE AND WEAR IN A JOURNAL BEARING

Sunday, November 15th, 2009

bearingsFATIGUE AND WEAR IN A JOURNAL BEARING (during start-up and boundary lubrication)

When two bodies are pressed together contact stresses occur. The results of the work done in this area are due to Hertz and are referred to as Hertzian stresses. Two special cases of hertzian stresses are: contacting spheres and contacting cylinders. An example of contacting spheres would be a single row ball bearing, with a single ball contacting the inner surface of the inner or outer race. An example of contacting cylinders would be a Read more…

PRINCIPLES OF JOURNAL BEARING DESIGN

Monday, October 12th, 2009

bearingsThe purpose of a bearing is to support a load. Deflection of the journal within the bearing can adversely affect the load carrying ability of the bearing. This deflection can be greatly reduced by increasing the diameter of the journal and decreasing its length. This results in a short bearing with a consequential greater flow of oil out of the ends of the bearing. This outflow of oil transfers heat from the bearing and helps to reduce the bearing temperature.
The factor which controls the length of the bearing to the journal diameter, is known as the L/D ratio. Read more…

BEARING THE BRUNT

Sunday, September 13th, 2009

bearingsFor all of its engine bearing needs in NASCAR Camping World Truck Series (CWTS) engines, PME Engines of Mooresville, North Carolina has researched heavily to meet its main and rod end requirements.

On a mile-and-a-half oval like Chicagoland Speedway, where the CWTS raced the final weekend of August, PME owner Mark Smith acknowledged that he is “always fighting temperatures because they never lift here. They’re running wide open throttle all the time, so the temperatures are always up and you always have Read more…