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pressure under which they were manufactured, and may be charged with oil. They thus become self-lubricating and suitable for places where regular maintenance is difficult or impossible. They are often used in small appliances and fractional hp-motors.

烧结轴承通过在模具内压缩主要金属粉末的混合物，并随后烧结在烘箱压块制成。所用的粉末是主要的铜和锡的混合物，有时是铁，与其它某些期望属性粉末材料混合。有时加入少量石墨到粉末混合物中，给应用于摆动和往复运动的轴承提供一定量的润滑。这种轴承都是或多或少多孔的，这取决于下它们被制造的压力，并且可以被装入油。因此它们成为自润滑部分，它的常规维护很困难甚至不可能。它们经常用于小型电器和分数马力电机。

Recent Developments in Bearing Technology 轴承技术的最新发展 Electromagnetic Bearings 电磁轴承

In these bearings, the journal floats on a repulsing magnetic field and is kept in a central position between the magnets by corrective signals from sensors between the magnet poles. An application of these bearings usually comprises two radial and one axial (thrust) bearing. Since there is no physical contact between journal and magnets during rotation, there is no wear. Other advantages are:

在这些轴承中，该轴颈漂浮在一个排斥磁场上，并通过来自磁铁两极传感器的纠正信号保持在磁体的中央位置。这些轴承的应用通常包括两个径向和一个轴向（推力）轴承。由于在旋转期间轴颈和磁体之间没有物理接触，所以没有磨损。其他的优点是：

1 Absence of noise

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没有噪音

2 No seals or lubricants required 无需密封或润滑剂

3 Insensitivity to ambient temperatures (operating range is -150 to 450 F)

不敏感的环境温度（工作范围为-150至450°F）

4 Operation possible in a vacuum or in corrosive atmospheres

在真空或在腐蚀性环境中操作成为可能

5 Small losses( from hysteresis and eddy currents ) ，hence small temperature rise

损失小（磁滞和涡流），因此，升温小

6 High potential circumferential velocities (up to 600 fms) 高电位圆周速度（高达600 FMS）

Magnetic bearings were originally developed for light loads in earth-orbiting satellites but are beginning to be used in industrial equipment. Journal materials are limited to ferromagnetic types.

最初开发的磁性轴承用于轻负载地球轨道卫星，但也开始在

工业设备中使用。轴颈材料限于铁磁类型。 Foil Bearings 箔片轴承

Foil bearings are a type of gas bearing with improved properties. They were developed to overcome operation instabilities inherent with gas bearings ( half- and full-frequency whirl ) and seizing at high temperatures, at which the clearance may become zero. Half- and full-frequency whirl are

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unstable conditions of journal vibration with a frequency equal to the rpm or half the rpm. The phenomenon occurs mainly in lightly loaded bearings.

箔片轴承是提高性能的一种气体轴承。它们被开发以克服在高温下间隙可以变为零时出现的气体轴承（半桥和全频涡动）操作不稳定或卡住。半频和全涡动频率是频率等于所述rpm或半rpm的轴颈振动不稳定条件。这种现象主要发生在轻载轴承。 Foil bearings also have improved load capacities. In the 1-2 in. diameter range, bearing pressures may be as high as 30 psi. 箔片轴承还具有良好的承载能力。在1-2英寸的直径范围，轴承压力可以高达30磅。

In these bearings, thin, flexible surfaces made from metal foils, which may be as thin as 0.001 in., replace the rigid surface of conventional gas bearings. The flexible foil adapts itself to changing load conditions and maintains a constant gas film thickness, thus damping out load variations and reducing the tendency to whirl. Foil bearings are also less sensitive to minor misalignment and journal irregularities, and unlike plain gas bearings, permit the passage of dust or dirt particles. Also, during starts and stops, the load is distributed over a larger area than in plain gas bearings, where there is essentially line contact between journal and bearing surfaces. Wear is thus reduced. 在这些轴承中，薄的，柔性的表面由薄于0.001的金属箔制成，取代的常规气体轴承的刚性表面。柔性箔调整自身适应变化的负载条件和保持恒定的气体膜的厚度，从而阻尼出负荷的变化和减少旋转的倾向。箔轴承对轻微错位和轴颈不规则规较不敏感，而不像普通的气体轴承，可以使灰尘或污物颗粒通过。此外，在启动和停止时，负载被分布的区域比普通气体轴承更大，轴颈与轴承面之间基本上是线接触。从而减少磨损。

There are two basic types of foil bearings, tension-dominated and bending dominated. Since metal-to-metal

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contact exists during start-up and stopping, foils or journals must have special coatings to reduce friction and wear. Foil bearings are often used in high-temperature applications, such as gas turbines(-65 to 1200 F),so that that materials selected for this type must be able to withstand these conditions.

有两种基本类型的箔轴承，张力为主和弯曲为主。由于在启动时和停止存在金属对金属的接触，箔片或轴颈必须有特殊的涂层，以减少摩擦和磨损。箔轴承通常用于高温应用，例如燃气轮机（-65到1200 F）中，因此，选择的这种类型的材料必须能满足这些条件。

Bearings with rolling contact 滚动轴承

In bearings with rolling contact, the shaft are directly or indirectly supported by rolling elements, such as balls, cylindrical or conical rollers, or needles(i.e., cylindrical rollers with a high L/D ration). The occasionally encountered name 'anti-friction bearings' suggests that this type has little or no friction. This is erroneous, since the friction is merely of another nature than in journal bearings. In bearings with rolling contact, friction losses are caused by the elastic deformation of the surfaces in rolling contact, sliding friction of rolling elements with cages, retaining rings and seals, or with one another, and also by some shear of lubricant.

在轴承滚动中，轴直接或间接地通过滚动元件，诸如滚珠，圆柱或圆锥滚子，或针（即，圆柱滚子具有高的L / D比）的支持。偶尔遇到'防摩擦轴承'，就认为这种类型具有很少或没有摩擦。这是错误的，因为这仅仅是另一种性质相对于轴颈轴承的摩擦。在轴承的滚动接触，导致摩擦损耗的因素有：滚动接触表面的弹性变形，滚动元件和保持架间、保持环和密封件、或者与另一个的滑动，或者润滑剂的一些剪切摩擦。

The following types of bearings with rolling contact are in

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