Types of Bearings.doc

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Types of Bearings
There are many tapes of bearings of variations in the design of rings and separators and in the number of balls. They can be divided into classes according to their function; those that support a radial, those that support a thrust load, or those that support a combination of thrust and radial loads.
1. Deep groove radial ball bearings
In deep-groove ball bearings, the races are approximately one-fourth as deep as the ball diameter, although deep-groove ball bearings are designed to carry a radial load. They perform well under a combined radial and thrust load. For this reason, it is the widely used type of ball bearing.
2. Filled-notch ball bearings
The most effective way of increasing bearing load ball capacity is to increase the ball complement. Filled-notch ball bearings are accomplished by cutting a notch in the races of a conventional bearing, thereby permitting the insertion of the balls. Once the balls have been inserted into the bearing through the notch is filled by an insert. The insert should be kept on the unloaded side of the bearing, for it weakens the race. The increase ball complement makes possible a 20 to 40 percent increase in radial-load capacity over that of the normal deep-groove bearing, depending on bearing size. The thrust capacity of the filled notch type is only20% of the thrust capacity of the deep-groove bearing.
3. Angular contact bearings
A unidirectional thrust bearing, which is the most popular form of angular contact bearings, is common to us. This type of bearing is designed to support combined radial and unidirectional thrust loads. The amount of thrust load that this bearing can support is heavier than the smaller-contact-angle. A contact angle of zero corresponds to a radial bearing; a contact angle of 90 degree corresponds to thrust bearing.
4. Self-aligning ball bearings
Self-aligning ball bearings normally have two rows of balls that roll in a common spherical race in the outer ring. Because of the design, the inner ring, with the ball complement, can align itself freely around the axis of the shaft. When the shaft bends under load, the bearing will follow the deflecting of the shaft without resistance, self-alignment also contributes to smooth running by neutralizing the effect of the ball wobbling in the grooves. This bearing is therefore particularly useful in applications in which it is difficult to obtain exact parallelism between the shaft and housing bores.
5. Thrust ball bearings
In the type of the simplest form of thrust balls, a single row of balls set in a separator runs in two similar grooves formed in the stationary and revolving rings. The revolving ring is fixed to a shaft. These grooves are usually shallower than the groove in a deep-groove radial ball bearing. Thrust ball bearings are designed to carry pure thrust load and, if any radial load is present, separated radial bearing must be used.
6. roller-bearing
Roller bearing serves the same purpose as ball bearings, but it can support much higher loads than comparably sized ball bearing because it has line contact instead of point contact .roller bearing can be classified into three basic types; cylindrical roller bearing, needle roller bearing and tapered and tapered roller bearing.
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译文；
因为内外圈和保持架设计的多样化以及滚珠数目的不同，所以轴承有许多类型。它们可以根据功能分为径向承载轴承轴向承载轴承以及径向承载轴承与轴向承载轴承的组合三种。
1． 在深沟径向球轴承；
在深沟径向球轴承中，滚道深度约为滚珠直径的1\4。尽管深沟径向球轴承是为承受径向载荷而设计的，但在径向载荷和轴向载荷同时作用下也工作较好，所以它是用途最广泛的一种球轴承。
2.填充式滚珠轴承；
提高轴承承载能力最有效的方式是增加滚珠数目。在填充式滚珠轴承的滚道上开一个槽，从哪儿填充滚珠来增加滚珠数目，当滚珠通过开口填充之后，用嵌块封住开口。由于开口会降低滚道的强度，所以嵌块必须设计在轴承不承载的一侧。增加滚珠之后根据轴承尺寸大小可以是常规深沟滚珠球轴承承载能力提高20%-40%。但其轴向承载能力仅为深沟滚珠球轴承的20%.
3.角接触轴承；
单一方向的推力轴承是最常见的角接触轴承，这类轴承的设计为组合支撑径向载荷和单向推力载荷，与小接触角轴承相比，这种轴承所能承受的推力载荷更大一些。接触角为零对应为径向轴承，接触角为90度的轴承为推力轴承。
4.自适应球轴承；
通常自适应球轴承与两列滚珠，它们在外圈的公共球面滚道中滚动。因为将其填满滚珠的内环设计成通过绕着轴的轴承自由调整，当轴承受载弯曲时，轴承可无阻力的跟随轴变形方向调整。自适应轴承可抵挡消滚珠在滚道中运动是所产生的振动影响，是轴承平稳运转。这类轴承特别是用于较难获得轴与轴承孔平行的场合。
5止推球轴承；
最简单的一类止推球轴承，保持架内的一列滚珠在静止和回转上的两个相同的滚道中滚动。旋转的环与轴固接，这些滚道通常要比深沟径向球轴承的浅。止推球轴承的设计是承受纯推力，如果有一点径向载荷，必须令安装径向轴承
6 滚珠轴承；
滚珠轴承与滚珠轴承的功能一样，但其承受的载荷要更大大高于相应尺寸的滚珠滚珠轴承，因为它是线接触而不是点接触。滚珠轴承可分为三种基本类型；圆柱滚子轴承 滚针轴承和圆锥滚子轴承。
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