Rolling bearing’s ferrule and the rolling body, withstand the high contact pressure repeatedly at the same time, at the same time carries on follows is having the glide rolling contact, simultaneously, maintains high accuracy revolving. Therefore, to bearing’s ferrule, the rolling body and retainer’s material, the performance, the overriding demand is as follows:
1. Because has the big partial contact stress, the request limit of elasticity is high;
2. Because withstands the big contact load repeatedly, the request trundle fatigue strength is high;
3. May obtain the high degree of hardness;
4. The resistance to wear are good;
5. Anti-impact load’s toughness is good;
6. The size stability is good.
In addition, it also need the workability to be good. Is different according to the use, but also has requests its impact resistance, the thermal stability, the inoxidizability to be good.
MATERIALS OF FERRULE AND ROLLING ELEMENT
Normal ferrule and rolling element both adopt high-carbon chromium ball bearing steels or cemented steel. It must be high fatigue strength and abrasive resistance. The ferrule adopts all-quenching. Both the surface and the core will be hardened. The rolling element adopts surface carburizing quenching. It only hardened on the surface. Usually the rigidity of ferule and rolling element is HRC58 to HRC65. For many cases, the selections of rolled steel are depending on processing technique it adopts. For instance, the out rings of some needle bearings are shaped by pulling and pushing.
High-carbon chromium ball bearing steels
High-carbon chromium ball bearing steels is the optimal for rolling bearing. It has wide range of application. It contains about 1% carbon and 1.5% chromium. For large-size cross section bearing component, the alloy steel that contains manganese and molybdenum is in common use. The two elements both have superior integral harden ability.
External hardened steel
The most common uses for external hardened steel are chromium nickel alloy steel and manganese chromium alloy steel.
HEAT RESISTANT BALL BEARING STEEL
Generally, the operating temperature of HBB rolling bearing can reach up to 125℃. If operating temperature above this value, the bearing, must be special heat-treated.(Anti-movement treatment), it should prevent dimensional change caused by structural change over within bounds. Yet it need not be stabilized to bearing in condition of it above required operating temperature. When the operating temperature of bearing over 300℃, it is necessary to use special steel with high heat hardness.
Corrosion resisting bearing steel
Chrome steel or chrome molybdenum stainless steel is often used by the bearing contact with corrosive media in operational process. For these steels is lower hardness, the bearing capacity of this bearing is lower than traditional steel bearing. Besides, it is possible to prevent corrosion if the entire surface is rubbed sleekly and no damaged in installing.
HBB adopts vacuum degassing bearing steel. The material is high-cleanliness, low oxygen, and good quality. In addition, proper heat treatment will help to increase the fatigue life of rolling bearing.
F & Z bearing retainer introduction
MATERIALS OF CAGE
The cage is mainly used for keeping apart the rolling elements, in order to prevent direct contact or dropping between adjacent rolling element. It maintains the bearing lowest temperature of friction and heating. For some types bearing, such an needle bearing or thrust bearing, cage is responsible for leading the rolling elements. For grease lubricated bearing, cage also works for reserving lubricant, in order to improve the lubrication of bearing.The mechanical stressed by rolling bearing cage is from friction force, and inertia force. It also influenced by some chemical reactions, such as lubricant additive and its aging product, organic solvent and liquid coolant. Therefore, it is vital to design and select the cage materials that are for the cage property and bearing running reliability.
According to various process features of cage, the adoptive materials mainly focus on: different pressed cages mostly adopt steel, brass Hpb59-1, bronze ,aluminum, and phenol aldehyde adhesive pipe, powder metallurgy and nylon66.
STANDARD CAGE
Series of different size of the bearing are set out in a cage for the type of structure standard bearings. This cage has been proved high performance through the appliance. It can be used in majority of applications. According to different requirements of product property, cost, and applications, the designs standard cages are distinct between bigger and smaller bearing.
The standard cage data is listed in the text display part in of bearing size table, and data of other possible adoptive cages.
STEEL CAGE
This type of cage has high strength with low weight. The cage usually needs quenching and surfacing treatment with the purpose of anti-attrition. It is more applicable to deep grove ball bearing, spherical roller bearing, and most cone roller bearing.
For the large bearings, mechanical cut steel cage is adopted if machined brass cage comes into seasonal break. For increasing the sliding moved capacity and abrasion resisting properties, some of the mechanical cut steel cage carburized onto surface hardening.
BRASS CAGE
Punching brass cage is only used in small-sized and middle-size bearing. Most brass cages are mechanical cut by casting or forging.
Brass cage is incapable of temperature above300℃. It would not be influenced by majority of common-used lubricant, so would synthetic oil and grease. It is cleaned with general organic solution, but not sig water.
NYLON CAGE
There are some kinds of small-sized bearing, such as double row deep groove ball bearing, self-aligning ball bearing, angular contact ball bearing, self-aligning ball bearing, angular contact ball bearing self-aligning roller bearing, and cylindrical roller bearing. They adopt cage materials after heat stabilized, elastic fiberglass nylon-66 compression molding. Because nylon works well on sliding and moving at lubricated steel surface, and cage contacts smoothly rolling element, the friction product by cage is substantially reducing. Hence, the heating and friction of bearing would reach to a low degree. Cage producing Shooting technique is satisfied with special design requirements. Nylon cage can keep operating performance well in condition of oil starvation. It makes the bearing running continuously quite a long time in mal-condition. There would not be locking in a short time or further damage. It needs be attention to the allowable temperature and anti-lubricated corrosion capacity of nylon materials when nylon cage works. For the bearing lubricated oil and grease, the property of cage would not be influence even under the operating temperatures data listed in the table below. If it reaches over the allowable operating temperature, the cage materials would be aging. The longer time it heated the faster process of aging.
The operating temperature of nylon cage is allowed momently exceed recommended temperature, but not over pass more than 20℃. The moment high-temp should be separated into longer time low-temp. It is attention whether the lubricant exceed temperature momently. When the operating temperature over 120℃, bearing with metallic cage is the choice. Also, nylon cage is not suitable for operating temperature below -40℃ because of lose of elastic.
The property of cage would not be influenced in short-time room temperature by using the rolling bearing cleaned organic solution, such as whitening cleaning oil, chloroform and dilute alkali lye -Freon or ammonia using in refrigeration plant has no erosion effect nylon. Nylon cage would became frangible in condition of vacuum. Table 3.3 shows the allowable temperature by using different lubricant onto fiberglass enhanced nylon66 cage.