6.9.2.10 In addition to the parameters used to perform, an undamped torsional natural frequency analysis as specified in 6.9.2.2, the following shall be included in the transient forced response analysis:

除了用于进行 6.9.2.2 中规定的无阻尼扭转固有频率分析的参数外，瞬态强迫响应分析还必须包括以下参数：

a)  motor average torque, as well as pulsating torque (direct and quadrature axis) vs speed characteristics;

电机平均转矩以及脉动转矩（直接轴和正交轴）与速度的关系特性；

b) load torque vs speed characteristics;

负载扭矩与速度的关系特性；

c) electrical system characteristics affecting the motor terminal voltage or the assumptions made concerning the terminal voltage, including the method of starting, such as across the line, or some method of reduced voltage starting.

影响电机端电压的电气系统特性或对端电压的假设，包括启动方法，如跨线启动或某种降压启动方法。

6.9.2.2 A forced response analysis shall generate the maximum torque and, in case of a transient forced response analysis, a torque vs time history for each of the shafts in the train.

强制响应分析应产生最大扭矩，如果是瞬态强制响应分析，则应有整个机组系列中每个轴的扭矩随时间变化的历史记录。

The maximum torques shall be used to evaluate the peak torque capability of coupling components, gearing and interference fits of components, such as coupling hubs, and shaft locations with stress raisers such as keyways. The torque vs time history shall be used to develop a cumulative damage-fatigue analysis of shafting, keys, and coupling components.

最大扭矩应用于评估联轴器部件、齿轮和过盈配合部件（如联轴器毂）的峰值扭矩能力，以及带有应力集中（如键槽）的轴位置。应使用扭矩与时间的历史记录对轴、键和联轴器组件进行累积损伤-疲劳分析。

6.9.2.3 Appropriate fatigue properties and stress concentrations shall be used.

应使用适当的疲劳特性和应力集中。

6.9.2.4 An appropriate cumulative fatigue algorithm shall be used to develop a value for the safe number of starts and/or short-circuit events. The purchaser and vendor shall mutually agree as to the safe number  of  such events.

应使用适当的累积疲劳算法来确定启动和/或短路事件的安全次数。买方和卖方应共同商定此类事件的安全次数。

NOTE Values used depend on the analytical model used and the vendor s experience. Values  of 1000 to 1500 starts    are common. API 541 requires 5000 starts, which is a reasonable assumption for a motor. The driven equipment, however, would be overdesigned to meet this requirement.

注：使用的数值取决于所使用的分析模型和供应商的经验。1000 到 1500 次启动的数值很常见。API 541 要求达到 5000 次启动，这对电机来说是一个合理的假设。不过，为满足这一要求，被驱动设备的设计将过于复杂。

解释：机组的启停是最容易出现问题的过程。

6.9.3 Balancing

平衡

6.9.3.1  Impellers, balancing drums, and similar major rotating components shall  be dynamically  balanced  to ISO 21940-11, Grade G2.5. The mass of the arbor used for balancing shall not exceed the mass of the component being balanced. Shafts are not required to be balanced. For single-stage BB1 and BB2 pump rotors with interference fit components, the vendor may choose to balance the assembled rotor (in accordance with 9.2.4.2) instead of balancing major rotating components individually.

叶轮、平衡鼓和类似的主要旋转部件必须按照 ISO 21940-11, G2.5 级进行动平衡。用于平衡的心轴质量不得超过被平衡部件的质量。轴无需进行平衡。对于带有过盈配合部件的单级 BB1 和 BB2 泵转子，卖方可选择平衡组装转子（符合 9.2.4.2），而不是单独平衡主要旋转部件。

解释：arbor（心轴）是一种用于平衡旋转部件的工具，它可以模拟部件在实际安装时的状态，将部件固定在平衡机上进行测量和校正。arbor的形状和尺寸要与部件的安装方式相匹配，例如锥度、孔径、键槽等。arbor的质量要小于或等于部件的质量，以避免增加平衡机的负载和误差。如下图，就是心轴，用心轴代替真正的轴，为什么不用真正的轴呢？arbor的长度和重量更适合平衡机的规格，不超过平衡机的最大容量。arbor的形状和结构更适合平衡机的夹持方式，能够牢固地固定在平衡机上，且不影响平衡机的旋转。

NOTE In ISO 21940-11 standards, unbalance is expressed as a balance quality grade. Each of the ISO balance quality grades covers a range of unbalance. The nominal equivalent USC unit limits given throughout this standard correspond approximately to the midpoint of the ISO range.

注：在 ISO 21940-11 标准中，不平衡度以平衡质量等级表示。ISO 平衡质量等级中的每个等级都涵盖一定范围的不平衡度。本标准中给出的标称等效 USC 单位限值大致相当于 ISO 范围的中点。

解释：平衡等级从G0.4到G400大致分为11个等级。每一个等级有不同的不平质量要求。

6.9.3.2 Component balancing may be single-plane if the ratio D/b (see Figure 30) is 6 or greater.

如果比率 D/b（见图 30）为 6 或更大，则可采用单面平衡。

解释：平衡分为静平衡和动平衡，静平衡又成为单面平衡，动平衡又称为双面平衡。如果D/b的数值≥6，说明所平衡部件更像一个厚度很小的大圆盘，因此采用静平衡就能满足平衡要求。

6.9.3.3  Rotor balancing shall be performed as required in the specific pump sections.

必须按照泵的具体章节要求进行转子平衡。

解释：说的就是按照第9章内容进行

6.9.3.4 If specified, impellers, balancing drums, and similar rotating components shall be dynamically balanced to ISO 21940-11, Grade G1.

如有规定，叶轮、平衡鼓和类似的旋转部件必须按照 ISO 21940-11 G1 级进行动平衡。

解释：一般对于泵来说，G2.5的动平衡等级就够了

a)  Single-suction Impeller单吸叶轮

b) Double-suction Impeller双吸叶轮

c) Thrust Collar推力盘

d) Balancing Drum平衡鼓

Key：

b width宽度

D diameter直径 

Figure 30 Rotating Component Dimensions to Determine if Single-plane Balancing Is Allowable

图30—转子部件尺寸来确定是否允许单面平衡

6.9.3.5 If specified, impellers, balancing drums, and similar rotating components shall be dynamically balanced to:

如果有规定，叶轮、平衡鼓和类似的旋转部件必须进行动平衡，以：

U = 4W/n

In USC units where

USC单位制，式中

U is the unbalance per plane, expressed in ounce-inches;

U 是每个平面的不平衡度，单位为盎司-英寸

W is the component mass (for components), expressed in pounds; or the load per balancing machine journal (for rotors), expressed in pounds;

W  是组件质量（对于组件），以磅为单位；或每个平衡机轴颈的负载（对于转子），以磅为单位

n  is the rotational speed of the pump, expressed in revolutions per minute.

n 是泵的转速，以每分钟转数表示

NOTE 4W/n is a balance tolerance denominated solely in USC units. With modern balancing machines, it is feasible to balance components mounted on their arbors to U =4W/n (USC units), or even lower depending upon the mass of the assembly, and to verify the unbalance of the assembly with a residual unbalance check. However, balancing to ISO Grade G1 or U =4W/n (USC units) is generally not repeatable when the components are dismantled and  remounted  on  their  arbors, because of the minute mass eccentricity values associated with these fine levels of unbalance requirements. See 9.2.4.2.2.

注：4W/n 是仅以 USC 单位表示的平衡公差。使用现代平衡机，可以将安装在心轴上的组件平衡至 U=4W/n（USC 单位），甚至更低，这取决于组件的质量，并通过残余不平衡检查来验证组件的不平衡。然而，当组件被拆卸并重新安装到心轴上时，ISO G1 级或 U= 4W/n（USC 单位）的不平衡度通常是不可重复的，因为与这些微小的不平衡度要求相关的质量偏心值很小。参见 9.2.4.2.2。

解释：G1的复现度很低。第一次试验达到了G1的平衡等级，如果重复试验，可能就达不到了。

6.9.4 Vibration

振动

6.9.4.1 Centrifugal pump vibration varies with flow, usually being a minimum in the vicinity of BEP flowrate and increasing as flow is increased or decreased. The change in vibration as flow is varied from BEP flowrate depends upon the pump s energy density, its specific speed, and its suction-specific speed. In general, the change in vibration increases with increasing energy density, higher specific speed, and higher suction-specific speed.

离心泵的振动随流量而变化，通常在最佳效率点附近为最小值，随着流量的增减而增大。流量从最佳效率点开始改变时，泵的振动变化取决于泵的能量密度、比转速和吸入比转速。一般来说，振动的变化随着能量密度的增加、比转速的提高和吸入比转速的提高而增大。

解释：大泵的能量密度更大，比转速也高，吸入比转速也高，因此偏离最佳效率点时，振动增大量更大。

With these general characteristics, a centrifugal pump’s operating flow range can be divided into two regions, one termed the preferred operating region, over which the pump exhibits low vibration, the other termed the allowable operating region, with the limits both high and low, defined as those flowrates at which the pump s vibration  reaches a higher but still “acceptable” level. Figure 31 illustrates the concept. Factors other than vibration, e.g. temperature, rise with decreasing flow, or NPSH3 with increasing flow, can dictate a narrower allowable operating region.

根据这些一般特性，离心泵的工作流量范围可分为两个区域，一个称为优先工作区域，在该区域内泵的振动较小；另一个称为允许工作区域，其极限既高又低，定义为泵的振动达到较高但仍 "可接受 "水平的流量。图 31 举例说明了这一概念。除振动之外的其他因素，如温度随流量降低而升高，或 NPSH3 随流量增加而升高，都可能导致允许工作区变窄。

解释：温度之所以随着流量降低而升高，是因为流量降低，效率降低，导致损失都转化成了热能。

优先工作区和允许工作区是最常用的两个概念。

The allowable operating region shall be stated in the proposal. If the allowable operating region is limited by a factor other than vibration, that factor shall also be stated in the proposal.

应在投标书中说明允许工作区。如果允许的工作区受到振动以外因素的限制，也应在投标书中说明该因素。

6.9.4.2  During the performance test, overall vibration measurements over a frequency range of 5 Hz  to  1000 Hz and discrete vibration measurements using fast Fourier transform (FFT) spectra shall be made at a minimum of five test points. These points shall include the rated flow point and the points defining the minimum and maximum flows for the allowable and preferred operating ranges. Vibration measurements are not required at shutoff. Vibration measurements shall be made at the following locations:

在性能试验期间，必须在至少五个试验点上，进行频率范围为 5 赫兹至 1000 赫兹的振动测量和使用快速傅立叶变换频谱的离散振动测量。这些测试点应包括额定流量点以及确定允许和优先工作区的最小和最大流量点。关闭点的位置不需要进行振动测量。必须在以下位置进行振动测量：

解释：5个点（额定流量点，允许工作区的最大和最小点，优先工作区的最大点和最小点。）

FFT就是快速傅里叶变化，将振动从时域改为频域，就能很好的看出具体在哪个频率上振动贡献最大。

a) on the bearing housing(s) or equivalent location(s) of all pumps, at the positions shown on Figure 32, Figure 33, and Figure 34 (it is recommended that vibration readings be taken in both horizontal and vertical planes at the rated point and at all other points in the same plane as the higher reading);

在图 32、图 33 和图 34 所示位置的所有泵的轴承箱或同等位置上 （建议在额定流量点下的水平和垂直平面上以及与较高振动读数同一平面上的所有其他点上采集振动读数）；

解释：一般就是图 32、图 33 和图 34上的H和V方向，或者X和Y方向测量振动。

b) on the shaft of pumps with hydrodynamic bearings both X and Y, if the pump has provisions for proximity probes.

带有 X 和 Y 流体动压轴承的泵轴上，如果该泵配有接近式探头。

解释：接近式探头，就是电涡流探头，如本特利3300系列。

6.9.4.3 The FFT spectra shall include the range of frequencies from 5 Hz to 2Z times running speed (where  Z is the number of impeller vanes; in multistage pumps with different impellers, Z is the highest number of impeller vanes in any stage). The plotted spectra shall be included with the pump test results.

FFT 频谱应包括从 5 赫兹到 2Z 倍运行速度的频率范围（其中 Z 为叶轮叶片数；在具有不同叶轮的多级泵中，Z 为任何一级中的最高叶轮叶片数）。绘制的频谱图应与泵测试结果一起提供。

解释：Z一般为质数，如5，7，11等。频谱图如下图所示。

NOTE The discrete frequencies 1.0, 2.0, and Z  times running speed are associated with various pump phenomena  and  are, therefore, of particular interest in the spectra.

注：1.0、2.0 和 Z 倍运行速度的离散频率与各种泵现象有关，因此在光谱中特别引人关注。

解释：泵现象指的是，不对中，不平衡等振动现象，往往和1倍，2倍，Z倍频率有关。Z就是叶轮叶片数。

6.9.4.4 Bearing-housing overall vibration measurements shall be made in root mean square (RMS) velocity, expressed in inches per second (millimeters per second).

轴承承座整体振动测量应采用均方根（RMS）速度，单位为英寸/秒（毫米/秒）。

解释：此为壳振，壳振用mm/s表示。

6.9.4.5 Shaft vibration measurement shall be peak-to-peak displacement, in mils (micrometers).

轴振动测量应为峰-峰位移，单位为密耳（微米）

解释：此为轴振，轴振用微米表示。

Key

X    flowrate流量

Y1 head扬程

Y2 vibration振动

1 allowable operating region of flow允许工作区

2 preferred operating region of flow优先工作区

3 maximum allowable vibration limit at flow limits流量范围内的最大允许振动极限

4 basic vibration limit基本振动极限

5 best efficiency point, flowrate最佳效率点，流量

6 typical vibration vs flowrate curve showing maximum allowable vibration典型振动与流量关系曲线，展示出最大允许振动

7 head-flowrate curve扬程流量曲线

8 best efficiency point, head and flowrate最佳效率点，扬程和流量

Figure 31 Relationship Between Flow and Vibration

图31—流量和振动之间的关系

解释：在优先工作区2的范围内，测量的振动应该在4的横线下（壳振对应的数值为3mm/s），在优先工作区外，但是仍然在允许工作区1的范围内，测量的振动应该在3的横线下（壳振对应的数值为3.3mm/s）

Dimensions  in  inches (millimeters)

用英寸（mm）表示的尺寸 

Key关键点

1 dimple (see 6.10.2.12)凹槽（见6.10.2.12）

2 optional arrangement for mounting vibration-measuring equipment (see  6.10.2.13)

安装振动测量设备的可选布置（见 6.10.2.13）

A axial轴向

H horizontal 水平向

V vertical 竖直向

Figure 32 Locations for Taking Vibration Readings on OH and BB Type Pumps

图32—在OH和BB型泵上测量振动读数的位置

Dimensions in inches (millimeters)

用英寸（mm）表示的尺寸

Key

1 driver mounting surface 电机安装面

2 pump bearing housing 泵轴承箱

3 dimple (see 6.10.2.12)凹槽（见6.10.2.12）

4 optional arrangement for mounting vibration-measuring equipment (see  6.10.2.13)

 安装振动测量设备的可选布置（见 6.10.2.13）

A axial 轴向

Figure 33 Locations for Taking Vibration Readings on Vertically Suspended (VS) Pumps

图33—在VS型泵上测量振动读数的位置

Dimensions  in  inches (millimeters)

用英寸（mm）表示的尺寸

 a)  Vertical In-line (OH3) Pump

立式管道泵OH3

b) High-speed Integrally Geared (OH6) Pump

集成齿轮的高速泵OH6

c)  Dimples凹槽 (see 6.10.2.12)

d)  Arrangement for Mounting Vibration-measuring Equipment安装振动测量设备的可选布置

(see 6.10.2.13)

Key

1 driver mounting surface电机安装面

2 pump bearing housing泵轴承箱

3 gearbox housing齿轮箱

4 suction flange吸入法兰

5 discharge flange排出法兰

6 threaded connection for stud-mounting vibration sensor螺纹连接，用于螺柱安装振动传感器

 A axial轴向

Figure 34 Locations for Taking Vibration Readings on Vertical In-line (OH3) and High-speed Integrally Geared (OH6) Pumps

图34—立式管道泵OH3和高速集成齿轮泵OH6的测振位置

6.9.4.6 The vibration measured during the performance test shall not exceed the values shown in the following:

性能试验期间测得的振动不得超过下列数值：

a)  Table 8 for overhung and between-bearing pumps 表 8 适用于悬臂泵和两端支撑泵

b) Table 9 for vertically suspended pumps,表9适用于立式悬吊泵

c) Figure 35 for high-energy pumps.图35使用图高能泵

Pumps furnished with proximity probes shall meet both bearing-housing and shaft-vibration limits.

如果泵配置了接近式探头，那应该既遵守轴承箱振动限制，也遵守轴振限值

解释：这条需要注意，有些滑动轴承的泵不设置轴振，那么就要遵守壳振（轴承箱振动）的要求。

NOTE Bearing housing overall vibration limits are defined for RMS measurements only.

注：轴承箱整体振动限值仅用于有效值测量（RMS）。

Table 8 Vibration Limits for Overhung and Between-bearings Pumps

表8—悬臂和两端支撑泵的振动限值

Table 9  Vibration Limits for Vertically Suspended Pumps立式悬吊泵振动限值

6.9.4.7 At any speed greater than the maximum continuous speed, up to and including the trip speed of the driver, the vibration shall not exceed 150 % of the maximum value recorded at the maximum continuous speed.

Vibration exceeding this limit, but below the allowable limit in the table may be accepted with purchaser's approval.

在任何大于最大连续转速的速度下，直至并包括驱动机的跳闸转速，振动不得超过在最大连续转速下记录的最大值的 150%。超过此限值但低于表中允许限值的振动，经买方批准后可以接受。

解释：比如最大连续转速下的振动为1mm/s，则跳闸转速下最大为1.5mm/s，但是如果实际跳闸转速下为3mm/s，虽然超过了1.5但是仍然在表格的要求内。

6.9.4.8 Variable-speed pumps shall operate over their specified speed range without exceeding the vibration limits of this standard.

变速泵应在规定的转速范围内运行，不得超过本标准规定的振动限值。

6.9.4.9  If the vendor can demonstrate that electrical or mechanical runout is present, the demonstrated amount of runout can be vectorially subtracted from the measured vibration during the factory test as long as it does not exceed 25 % of the allowed peak-to-peak vibration amplitude or 0.25 mil (6.5 μm), whichever is less.

 如果卖方能证明存在电气或机械跳动，只要不超过允许振动峰-峰振幅的 25% 或 0.25 mil (6.5 μm)（以较小者为准），则可在出厂测试时从测量振动中矢量减去所证明的跳动量。

解释：这句话的意思是，电气或者机械跳动属于干扰项，可以在测量的振动中矢量减去。

Key

X rotational speed, n expressed in revolutions per minute

转速，n表示为转每分钟

Y1 vibrational velocity, vu expressed in millimeters per second, RMS

振动速度，vu表示为mm/s，RMS（均方根）

Y2 vibrational velocity, vu expressed in inches per second, RMS

振动速度，vu表示为in/s，RMS（均方根）

1      P ≥ 3000 kW/stage（级）

2      P  = 2000 kW/stage（级）

3      P  = 1500 kW/stage（级）

4      P  = 1000 kW/stage（级）

5      P = 700 kW/stage（级）

6      P = 500 kW/stage（级）

7      P    300 kW/stage（级）

NOTE 1 The equation for transition from 3.0 mm/s to 4.5 mm/s is:  vu=3.0(n/3600)0.3[P/300]0.21

注1：从3.0mm/s到4.5mm/s的变换公式如下：vu=3.0(n/3600)^0.3[P/300]^0.21

NOTE 2 The allowable vibration limit for discrete frequencies is: v_f＜0.67v_u from Figure 35.

注2：对于离散频率的允许振动显示是：表格35中v_f＜0.67v_u

 Figure 35 Bearing Housing Vibration Limits for Horizontal Pumps Running Above 3600 r/min or Absorbing More Than 400 hp (300 kW) per Stage

图35—大于3600r/min或者单级功率超过400hp（300kw）水平泵的轴承箱振动限值

解释：由此可见，对于高能泵，其振动限制比一般泵高，要求更宽松。

6.10 Bearings and Bearing Housings

轴承和轴承箱

6.10.1    Bearings

轴承

6.10.1.1 Each shaft shall be supported by two radial bearings and one double-acting axial (thrust) bearing. If the pump has rolling-element radial and thrust bearings, the thrust bearing carries both the radial load on one end of the rotor and the axial thrust transmitted by the pump to the rotor. If the pump has hydrodynamic radial bearings and a rolling-element thrust bearing, the rolling-element bearing carries axial thrust only; the hydrodynamic bearings carry only radial loads. For higher loads and/or speeds, the hydrodynamic radial bearings carry all the radial loads and the hydrodynamic thrust bearing carries all the axial load.

每根轴应由两个径向轴承和一个双作用轴向（推力）轴承支撑。如果泵有滚动体径向轴承和推力轴承，则推力轴承既承受转子一端的径向载荷，又承受泵传递给转子的轴向推力。如果泵具有流体动压径向轴承和滚动体止推轴承，则滚动体轴承仅承受轴向推力；流体动压轴承仅承受径向载荷。对于较高负载和/或速度，流体动压径向轴承承受所有径向负载，流体动压推力轴承承受所有轴向负载。

解释：就是滚动径向+滚动推力

滑动径向+滚动推力

滑动径向+滑动推力，一共三种方案。

Bearings, therefore, shall be one of the following arrangements:

轴承，因此，应该是下面配置中的一种

a)  rolling-element radial and thrust;滚动径向和推力轴承

b) hydrodynamic radial and rolling-element thrust;流体动压静压轴承和滚动推力轴承

c) hydrodynamic radial and thrust.流体动压的径向和推力轴承

6.10.1.2 Unless otherwise specified or approved by the purchaser, the bearing type and arrangement shall  be selected in accordance with the limitations in Table 10.

除非另有指定或买方同意，轴承类型和配置应该根据表10的限制选择。

解释：表10很有用，规定了如何选用轴承。

6.10.1.3 For pumps that will be installed in oilfield and pipeline applications, rolling-element radial and/or thrust bearings may be applied exceeding Table 10 limits  with purchaser’s approval.

对于将安装在油田和管道应用中的泵，经买方批准，可使用超过表 10 限值的滚动元件径向和/或推力轴承。

解释：对于油田和管线的泵，其轴承的要求更加宽松。

Table 10 Bearing Selection

表10-轴承选择

6.10.1.4 Thrust bearings shall be sized for continuous operation under all specified conditions, including maximum differential pressure, and comply with the following.

推力轴承的尺寸必须满足在所有规定工况下（包括最大压差）连续运行的要求，并符合下列规定：

a) All loads shall be determined at design internal clearances and also at twice design internal clearances.

所有荷载均应在标准设计内部间隙和两倍设计内部间隙时确定。

解释：根据上表选定了轴承的形式，那轴承大小则要根据轴承所受的载荷确定了。载荷的大小与泵内部的设计间隙息息相关

比如，带有平衡鼓的泵，它与泵壳体的间隙与推力轴承的受力息息相关，平衡鼓的间隙越大，则轴承承受的推力越大，本条要求设计时考虑1~2倍的间隙，这个要求和前面要求的按照1~2倍运行间隙来计算液体刚度的要求是一样的。

b)  Thrust forces for flexible metal-element couplings shall be calculated on the basis of the maximum allowable deflection permitted by the coupling manufacturer.

弹性金属元件联轴器的推力应根据联轴器制造商允许的最大挠度计算。

解释：很少有泵厂会考虑由联轴器传递过来的推力。

c) If a sleeve-bearing motor (without a thrust bearing) is directly connected to the pump shaft with a coupling, the coupling-transmitted thrust shall be assumed to be the maximum motor thrust.

如果套筒轴承电机（无止推轴承）通过联轴器直接与泵轴连接，则应将联轴器传递的推力假定为电机的最大推力。

解释：因为电机无推力轴承，电机的推力也会通过联轴器传递给泵。

d) In addition to thrust from the rotor and any internal gear reactions due to the most extreme allowable conditions, the axial force transmitted through flexible couplings shall be considered a part of the duty of any thrust bearing.

除了来自转子的推力和任何内部齿轮反作用力（由于最极端的允许条件而产生的）之外，通过弹性联轴器传递的轴向力也应视为任何推力轴承工作的一部分。

e) If specified, the angular contact thrust bearing may be mounted on a removable sleeve that is retained on the shaft by a locking nut and tab washer.

如有规定，角接触推力轴承可安装在一个可拆卸的轴套上，该轴套通过锁紧螺母和片状垫圈固定在轴上。

解释：下图是带有轴套的角接触球轴承，用锁紧螺母和tab washer固定的列子。但是一般来说，成对的角接触球轴承是不带轴套的。

NOTE This arrangement allows the thrust bearing to be easily removed for mechanical seal maintenance and then be reused.

注：这种布置可以方便地拆下止推轴承进行机械密封维护，然后重新使用。

6.10.1.5 Rolling-element bearings shall not have filling slots.

滚动轴承不得有填充槽。

解释：filling slot就是用来填充滚动原件的。如下图。

6.10.1.6 Rolling-element bearings shall not have nonmetallic cages.

滚动轴承不得使用非金属保持架。

解释：一般要求滚动轴承的保持架为金属的，最好是铜的。Cage就是保持架，如下图

6.10.1.7 Single-row, deep-groove ball bearings shall have a radial internal clearance in accordance with ABMA  20, Group 3 (large than ”N” or Normal internal clearance). Greater internal clearances can reduce the temperature rise of the lubricant. However, vibration velocities can be increased with greater clearances. The vendor shall ensure that the values for temperature rise and vibration meet the requirements of this standard.

单列深沟球轴承的径向内部游隙应符合 ABMA 20 第 3 组的规定（大于 "N "或正常内部游隙）。更大的内部游隙可降低润滑剂的温升。但是，间隙越大，振动速度越快。供应商应确保温升和振动值符合本标准的要求。

解释：ABMA 20, Group 3 是美国轴承制造商协会（ABMA）的一个标准，它规定了英制圆锥滚子轴承的代号和尺寸。

NOTE For the purpose of this provision, ISO 5753, Group 3 is equivalent to ABMA 20, Group 3.

注：就本规定而言，ISO 5753 第 3 组等同于 ABMA 20 第 3 组。

6.10.1.8 Ball  thrust  bearings  shall  be  of  the  paired,  single-row,  40°  (0.7 rad)  angular  contact  type (7000 series) with machined brass cages. Pressed steel cages may be used if approved by the purchaser. Unless otherwise specified, bearings shall be mounted in a paired arrangement installed back-to-back. The need for bearing clearance or preload shall be determined by the vendor to suit the application and meet the bearing life requirements of this standard.

推力球轴承应为成对、单列、40° (0.7 rad) 的角接触式（7000 系列），带有机加工黄铜保持架。如经买方批准，也可使用冲压钢保持架。除非另有规定，轴承应成对安装，背靠背安装。轴承间隙或预紧力的需求应由供应商确定，以适应工况并满足本标准对轴承寿命的要求。

解释：如下图，最常用的角接触7000系列成对出现的球轴承，下图黄色轴承。

NOTE There are applications where alternative bearing arrangements can be preferable, particularly where bearings operate continuously with minimal axial loads.

注：在某些应用中，替代性轴承布置可能更为理想，特别是在轴承连续运行、轴向载荷最小的情况下。

6.10.1.9 If loads exceed the capability of paired, angular-contact bearings as described in 6.10.1.10, alternative rolling-element arrangements may be proposed.

如果载荷超过 6.10.1.10 所述成对角接触轴承的能力，可建议采用其他滚动体布置。

解释：成对出现的圆锥滚子轴承的承载能力，比角接触球轴承更大。

6.10.1.10  Rolling-element bearing life (basic rating life, L10h, for each bearing or bearing pair) shall be calculated in accordance with ABMA 9 (ISO 281).

滚动轴承的寿命（每个轴承或每对轴承的基本额定寿命，L10h）应按照 ABMA 9 (ISO 281)计算。

解释：L10是指一批型号相同的轴承，在相同的工作条件下，其中90%能够达到或超过的疲劳寿命。它是一种基于概率的工具，用于确定足以避免疲劳失效的轴承尺寸，单位是百万转或者小时（小时更常用）

NOTE 1 ABMA 9 defines basic rating life, L10, in units of millions of revolutions. Industry practice is to convert this to hours and to refer to it as L10h .

注1：ABMA 9 以百万转为单位定义了基本额定寿命 L10。行业惯例是将其转换为小时数，并称为 L10h。