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李亚冰33、34页

(2009-10-27 10:17:33)
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Figure 1.72
Length changes of through-hardened, untempered 100 Cr 6depending on time and temperature. Initial state 20°C and I/I = 0 in volume. The total dimensional change is the net effect of the two volume changes (Figure 1.72).
通过硬化和未经锻造的100铬6的长度变化依赖时间和温度。初始状态20℃和I/I = 0
数量。总尺寸的变化是两个量的变化的净影响(图1.72)。
These dimensional changes are subject to the law of the smallest constraint. Tensional stresses, perhaps caused by an interference fit on the shaft, promote diameter increases. Rolling bearing manufacturers eliminate such dimensional changes by a defined tempering process after hardening. Retained austenite reduction and carbide precipitations in the martensite are anticipated by the tempering process. If bearings are not heated beyond the permissible maximum temperature (Table 1.7), the length changes illustrated in Figure 1.72 do not occur. Depending on the rolling bearing manufacturer, standard bearings are dimensionally stable up to 120 °C or 150 °C. The standardized stabilization grades of rolling bearings (Table 1.7) are guided by the highest operating temperature that occurs.
这些尺寸变化是受法则约束最小。张力过大,也许就造成轴过盈配合,促进直径增加。滚动轴承制造商通过界定回火过程等来消除淬火后的尺寸变化。减少残余奥氏体和马氏体碳化物的降水预计的回火工艺。如果轴承没有超出允许的最高温度(表1.7)加热,长度变化如图1.72不会发生。根据不同的滚动轴承制造商,标准轴承尺寸稳定可达120℃或150℃。被最高工作温度指导的滚动轴承标准化稳定等级(表1.7)发生。
The values in the table apply to through-hardened rolling bearing steels, especially to through-hardened chromium steels. Dimensional changes may also 

 

Table 1.7 Dimensional stability of bearings
Suffix for dimensionally Maximum operating
stabilized bearings temperature (°C)
no suffix 120
S0 150
S1 200
S2 250
S3 300

表1.7轴承尺寸稳定性三维后缀为最高工作稳定轴承温度(℃)
无后缀 120
S0 150
S1 200
S2 250
S3 300
   Page 50

occur in surface layer hardened components which, as a rule, are tempered at low temperatures. The dimensional changes are caused by structural changes in the surface layer. At higher operating temperatures, each individual case must be checked to see whether a special stabilizing treatment becomes necessary. The loss in hardness of dimensionally stabilized bearings and at high temperatures must be considered in the load rating calculation according to Figure 3.13b.
发生在表层加固组件,作为一项规则,是在低温锻炼。的尺寸变化是由于在表面层的结构变化。在更高的运行温度,每个案件必须进行检查,看看是否有特殊的稳定,在必要的治疗。在稳定的三维轴承硬度损失和必须在负载计算认为高温根据图3.13b。
Surface Treatment Processes 
表面处理工艺
For some time, substantial expenditure has been invested in the development of rolling bearing coatings. Some objectives of these surface treatment technologies are to improve the tribological behaviour (Section 4.3.6), sometimes obtained by coating the raceway surface of just one rolling contact partner; to increase the corrosion resistance; or to improve the insulation against electric current.
一段时间以来,大量支出已投资在滚动轴承涂料的发展。这些表面处理技术的一些目标是改善的摩擦学行为(第4.3.6节),有时涂料获得了只有一个滚动滚道表面接触的合作伙伴,以提高耐蚀性;或改进对电流的绝缘。
Black oxidizing or phosphatizing processes for improving the running-in behaviour or the capability to run without lubrication have been in use for quite a long time. A more modern process, tested in series applications, is the galvanic thin dense chromium coating (Figure 1.73). It improves the rolling contact fatigue behaviour and the wear resistance, especially under mixed friction conditions. Even after long running periods under rolling contact, reached with ideal lubricating conditions, the chromium layer must not peel. Due to the high hardness of the layer, peeled-off particles would quickly destroy the contact surfaces
黑色氧化或磷化改善运行过程中的行为和能力运行,而不润滑,已经使用了一段颇长的时间。一个更现代化的过程中,一系列应用测试,是电流密度镀铬薄(图1.73)。它提高了滚动接触疲劳的行为和特别是在混合摩擦条件下的耐磨性。即使经过长时间滚动接触下运行期间,与理想的润滑条件达成,铬层不能剥离。由于层硬度高,颗粒脱落,会很快破坏了接触面
An overall chromium coating improves the corrosion resistance of the generally used through-hardening rolling bearing steel. Coating by physical vapour deposition (PVD), coating by chemical vapour deposition (CVD) and surface layer modification by ion implantation, all three are being tested and are partly in use. Besides the technical criteria, the profitability of the bearing in question is decisive. Rolling bearing damage caused by the passage of electric current in special applications is eliminated by coating the outside diameters and faces of the bearing outer rings with insulating ceramic layers (Figure 1.74). These layers are applied by flame or plasma spraying.
一个总铬涂层提高了耐腐蚀性能的普遍使用,通过硬化滚动轴承钢。涂层的化学气相沉积(CVD)和表面层改性的物理气相沉积(PVD)涂层的离子注入,所有三个正在受到考验,并部分使用。除了技术标准,对有关轴承利润是决定性的。滚动轴承造成的破坏电力特殊申请的通道是由涂层消除了外径和轴承的外圈面临着陶瓷绝缘层(图1.74)。这些层已采用火焰或等离子喷涂。
1.2.2  Cage Materials
1.2.2  网箱材料
Rolling bearing cages are made of metal or plastic. Sheet steel or brass sheet are mainly used for the metal cages of smaller bearings; large and medium-size bearings have cold-formed or machined cages of brass or steel. Cages of bronze and aluminium alloy may be used for special applications.
滚动轴承保持架是由金属或塑料。钢板或黄铜板材,主要用于轴承的小保持架,大型和中型轴承冷弯或黄铜或不锈钢加工保持架。青铜和铝合金保持架可用于特殊应用。
For many years, rolling bearings of many types have been equipped with plastic cages. Thermoplastics have become important cage materials owing to their favourable sliding properties, their low weight and their elasticity; cages can be formed economically by injection moulding, even complicated shapes.
多年来,许多类型滚动轴承已配备塑胶保持架。热塑性塑料已成为重要的保持架材料由于其良好的滑动性能,低体重和弹性;保持架可形成注塑经济,更复杂的形状
Most plastic cages are made of the glass-fibre reinforced, thermoplastic material polyamide 66 (PA66.GF) and are heat-stabilized. They are suitable for steady-state operating temperatures of up to 120 °C. If the bearings are lubricated with oil, the cage service life may be reduced by additives contained in the oil, and possibly aged oil at higher temperatures. Therefore, the oil change intervals have to be observed. The effect of the steady-state temperature on the cage life is shown in Figure 1.75 [291a, 253a].
塑胶保持架大部分是由玻璃纤维增强的热塑性材料聚酰胺66(PA66.GF),而且热稳定。它们适合用于稳态操作温度高达120 ° C的如果轴承油润滑,使用寿命保持架,可减少石油添加剂中,并可能在较高温度下岁的石油。因此,换油间隔必须得到遵守。稳定的关于保持架生活状态温度的影响如图1.75 [291a,253a]。
page_51

 
Figure 1.73
Surface of a thin dense chromium-coated rolling element at magnification × 1000
图1.73
表面致密铬薄涂层滚动轴承在放大× 1000
 

Figure 1.74
Current-insulated deep-groove ball bearing
图1.74  电流绝缘深沟球轴承

 

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